Index

Numbers, expressions and equations

Integers, fractions and real numbers

  1. First calculate the following calculations without a calculator – “manually”.
    Then verify your answers with your GDC (Graphic Display Calculator).

    (a)   \((2+3\cdot 6)\cdot 5-1\)

    (b)   \(17-3\cdot(-4-2\cdot(-5))\)

    (c)   \(5\cdot(3^2-11)^3\)

    (d)   \(-3^2+(-2)^4\)

    (e)   \((-5^2+22)^3\)

    (f)   \(1+(-3)(-2)^2\)

    (g)   \(1+(-3)(-2^2)\)

    (h)   \(1+(-3(-2))^2\)

    Solutions:    (a)  \(99\);     (b)  \(-1\);     (c)  \(-40\);     (d)  \(7\);     (e)  \(-27\);     (f)  \(-11\);     (g)  \(13\);     (h)  \(37\)
  2. First calculate the following calculations without a calculator – “manually”.
    Then verify your answers with your GDC.

    (a)   \((-(1-(-2)(-1))-2-(-1)\cdot(-2))\cdot(-1)-2\cdot(-1)\)

    (b)   \(-\big(-1-(-2^2)\big)^2\cdot(-3)-(-3)^2\big(-2-(-1)\big)^3\)

    (c)   \(\big(-3-(-3)^2\big)\cdot3-2\cdot\Big(\big(2-(-2)\big)\cdot2-2^2\Big)\)

    Solutions:    (a)  \(5\);     (b)  \(36\);     (c)  \(-44\)
  3. First calculate the following calculations without a calculator and write the result as a fraction (or as a mixed number or an integer).
    Then verify your answers with your GDC.

    (a)   \(\left(\frac{5}{12}+\frac{7}{8}\right)\cdot\frac{32}{31}\)

    (b)   \(1\frac{3}{5}\cdot\left(7\frac{1}{8}-7\cdot\frac{1}{8}\right)\)

    (c)   \(\left(2-\frac{33}{10}\cdot\frac{5}{6}\right)^2\)

    (d)   \(\left(2\frac{8}{15}-\frac{1}{5}\right)^{-1}\)

    (e)   \(\left(\frac{13}{10}-\frac{1}{4}\right):\sqrt{2\frac{1}{4}}\)

    (f)   \(\frac{\textstyle\frac{12}{5}\times\frac{20}{28}}{\textstyle7\frac{1}{5}}\)

    (g)   \(\frac{\textstyle\frac{5}{12}+1}{\textstyle 3-\frac{1}{6}}\)

    (h)   \(\frac{\textstyle\frac{2}{3}}{\textstyle ~4~}-\frac{\textstyle ~2~}{\textstyle\frac{3}{4}}\)

    Solutions:    (a)  \(\frac{4}{3}\)  or  \(1\frac{1}{3}\);     (b)  \(10\);     (c)  \(\frac{9}{16}\);     (d)  \(\frac{3}{7}\);     (e)  \(\frac{7}{10}\);     (f)  \(\frac{5}{21}\);     (g)  \(\frac{1}{2}\);     (h)  \(-\frac{5}{2}\)  or  \(-2\frac{1}{2}\)
  4. First calculate the following calculations without a calculator and write the result as a reduced fraction.
    Then verify your answers with your GDC.

    (a)   \({\displaystyle\frac{2}{1+\frac{1}{5}}\cdot\Big(\frac{4}{75} +\frac{7}{50}\Big)\cdot3-\frac{1}{2}}\)

    (b)   \({\displaystyle\frac{3-\frac{1}{5}}{3+\frac{1}{5}}+\frac{31}{34}\cdot\frac{17}{62}}\)

    (c)   \({\displaystyle\left(\frac{1-\frac{1}{4}}{1+\frac{1}{2}} - 2^{-3}\right)\cdot\frac{190}{57} - 1}\)

    (d)   \(0.22\cdot\big(0.444+5^{-2}\big)^{-1}\)

    Solutions:    (a)  \(\frac{7}{15}\);     (b)  \(\frac{9}{8}\);     (c)  \(\frac{1}{4}\);     (d)  \(\frac{5}{11}\)
  5. First calculate the following calculations without a calculator and write the result in exact form (using fractions and roots).
    Then verify your answers with your GDC and write the results rounded to three significant figures.

    (a)   \((1+\sqrt{5}\,)\sqrt{5}\)

    (b)   \(\big(1-\sqrt{3}\,\big)^2\)

    (c)   \((\sqrt{18}-\sqrt{8}\,):15\)

    (d)   \(\sqrt{20}+\sqrt{45}-\sqrt{5}\)

    (e)   \(\sqrt{30}\cdot\sqrt{10}-\sqrt{6}\cdot\sqrt{2}\)

    (f)   \(\sqrt{7+\sqrt{22+\sqrt{9}\,}\,}\)

    (g)   \({\displaystyle\frac{13}{\sqrt{6}}-\frac{\sqrt{6}}{6}}\)

    (h)   \({\displaystyle\left(\sqrt{3}-\frac{2}{\sqrt{3}}\right)^3}\)

    Solutions:    (a)  \(5+\sqrt{5}\approx7.24\);     (b)  \(4-2\sqrt{3}\approx0.536\);     (c)  \(\frac{\sqrt{2}}{15}\approx0.0943\);     (d)  \(4\sqrt{5}\approx8.94\);     (e)  \(8\sqrt{3}\approx13.9\);     (f)  \(2\sqrt{3}\approx3.46\);     (g)  \(2\sqrt{6}\approx4.90\);     (h)  \(\frac{\sqrt{3}}{9}\approx0.192\)

Algebraic expressions

  1. Expand the following expressions (remove the brackets and write each expression as a sum of terms):

    (a)   \((x+2)(x-3)\)

    (b)   \((x-5)x+3\)

    (c)   \(1+(x-3)^2\)

    (d)   \((x-1)(x+2)(x-3)\)

    (e)   \((2x+1)^2-(x-2)^2\)

    (f)   \((-x)(x+2)-3(x-5)\)

    Solutions:    (a)  \(x^2-x-6\);     (b)  \(x^2-5x+3\);     (c)  \(x^2-6x+10\);     (d)  \(x^3-2x^2-5x+6\);     (e)  \(3x^2+8x-3\);     (f)  \(-x^2-5x+15\)
  2. Expand the following expressions:

    (a)   \(a^2(a+1)-(a-1)^2\)

    (b)   \((a+b)b+a(a-b)\)

    (c)   \((m+n+1)^2\)

    (d)   \((p+q)^3\)

    Solutions:    (a)  \(a^3+2a-1\);     (b)  \(a^2+b^2\);     (c)  \(m^2+2mn+n^2+2m+2n+1\);     (d)  \(p^3+3p^2q+3pq^2+q^3\)
  3. Factorise the following expressions (write each expression as a product of factors).
    Hint: factor out the common factor.

    (a)   \(x^2+7x\)

    (b)   \(5x^4+10x^2\)

    (c)   \(ab+b^2\)

    (d)   \(a^3+a^2b-abc\)

    Solutions:    (a)  \(x(x+7)\);     (b)  \(5x^2(x^2+2)\);     (c)  \(b(a+b)\);     (d)  \(a(a^2+ab-bc)\)
  4. Factorise the following expressions.
    Hint: use the Vieta's rule.

    (a)   \(x^2+8x+15\)

    (b)   \(x^2-8x+12\)

    (c)   \(a^2+a-6\)

    (d)   \(a^2-5a+6\)

    Solutions:    (a)  \((x+3)(x+5)\);     (b)  \((x-6)(x-2)\);     (c)  \((a+3)(a-2)\);     (d)  \((a-3)(a-2)\)
  5. Factorise the following expressions:

    (a)   \(x^3-4x^2-5x\)

    (b)   \(y^4+2y^3-24y^2\)

    (c)   \(a^3-6a^2+9a\)

    (d)   \(4k^3-8k^2-32k\)

    Solutions:    (a)  \(x(x+1)(x-5)\);     (b)  \(y^2(y-4)(y+6)\);     (c)  \(a(a-3)^2\);     (d)  \(4k(k+2)(k-4)\)
  6. Factorise the following expressions:
    Hint: use the formula \(a^2-b^2=(a-b)(a+b)\).

    (a)   \(x^2-25\)

    (b)   \(x^2-9\)

    (c)   \(4x^2-49\)

    (d)   \(9m^2-16\)

    (e)   \(49u^2-v^2\)

    Solutions:    (a)  \((x-5)(x+5)\);     (b)  \((x-3)(x+3)\);     (c)  \((2x-7)(2x+7)\);     (d)  \((3m-4)(3m+4)\);     (e)  \((7u-v)(7u+v)\)
  7. Factorise the following expressions:

    (a)   \(x^3-9x\)

    (b)   \(2a^4-8a^2\)

    (c)   \(a^3b-ab^3\)

    Solutions:    (a)  \(x(x-3)(x+3)\);     (b)  \(2a^2(a-2)(a+2)\);     (c)  \(ab(a-b)(a+b)\)
  8. Factorise the following expressions:

    (a)   \(x^4-10x^2+9\)

    (b)   \(x^4+5x^2-36\)

    (c)   \(a^4-5a^2+4\)

    (d)   \(a^4+5a^2+4\)

    Solutions:    (a)  \((x-1)(x+1)(x-3)(x+3)\);     (b)  \((x-2)(x+2)(x^2+9)\);     (c)  \((a-1)(a+1)(a-2)(a+2)\);     (d)  \((a^2+1)(a^2+4)\)
  9. Factorise the following expressions:

    (a)   \(x^3-2x^2-9x+18\)

    (b)   \(x^3-5x^2+4x-20\)

    (c)   \(y^3-y^2-25y+25\)

    (d)   \(y^4-y^3-y^2+y\)

    Solutions:    (a)  \((x-2)(x-3)(x+3)\);     (b)  \((x-5)(x^2+4)\);     (c)  \((y-1)(y-5)(y+5)\);     (d)  \(y(y-1)^2(y+1)\)

Equations

  1. Solve the following equations:

    (a)   \(8x-4=5(x+1)\)

    (b)   \(x^2+2x+8=(x-2)x\)

    (c)   \((x+2)^2-(x-1)^2= 9\,(x-3)\)

    (d)   \((x - 1)(x + 2)(x + 3) = x^3+4x^2+8x+16\)

    Solutions:    (a)  \(x=3\);     (b)  \(x=-2\);     (c)  \(x=10\);     (d)  \(x = -\frac{22}{7}\)
  2. Solve the following equations:

    (a)   \({\displaystyle\frac{x}{3}=\frac{x+2}{4}}\)

    (b)   \({\displaystyle\frac{x}{4}-4x=\frac{3x-7}{2}}\)

    (c)   \({\displaystyle\frac{x+5}{3} = 1+\frac{2}{3}\,\Big(x+\frac{1}{2}\Big)}\)

    (d)   \({\displaystyle\frac{1}{4}(x+2)^2-\Big(\frac{x-1}{2}\Big)^2=\frac{1}{4}+4x}\)

    (e)   \({\displaystyle\Big(\frac{x+1}{2}\Big)^3=\frac{1}{8}(x^3+3x^2)-1}\)

    Solutions:    (a)  \(x=6\);     (b)  \(x=\frac{2}{3}\);     (c)  \(x=1\);     (d)  \(x=\frac{1}{5}\);     (e)  \(x=-3\)
  3. Solve the following equations:

    (a)   \({\displaystyle\frac{1}{2x+1}=\frac{1}{3x-2}}\)

    (b)   \({\displaystyle\frac{x+1}{x-1}=\frac{3}{2}}\)

    (c)   \({\displaystyle\frac{x}{x+2}+\frac{3}{x-2}=1}\)

    (d)   \({\displaystyle\frac{2x}{x-2}=\frac{x+2}{x-2}}\)

    Solutions:    (a)  \(x=3\);     (b)  \(x=5\);     (c)  \(x=-10\);     (d)  No solution: \(x\) doesn't exist.
  4. Solve the following equations.
    Hint: Use zero product property (when product is equal to zero – what can you tell about factors?).

    (a)   \((x-2)(x-5)=0\)

    (b)   \((x-4)(x+1)=0\)

    (c)   \((x-1)(x-4)(x+6)=0\)

    (d)   \(x(x-3)(x+7)=0\)

    Solutions:    (a)  \(x_1=2,~ x_2=5\);     (b)  \(x_1=4,~ x_2=-1\);     (c)  \(x_1=1,~ x_2=4,~ x_3=-6\);     (d)  \(x_1=0,~ x_2=3,~ x_3=-7\)
  5. Solve the following equations using factorisation:

    (a)   \(x^2-5x+6=0\)

    (b)   \(x^2+2x-15=0\)

    (c)   \(x^3-2x^2-8x=0\)

    Solutions:    (a)  \(x_1=2,~ x_2=3\);     (b)  \(x_1=3,~ x_2=-5\);     (c)  \(x_1=0,~ x_2=-2,~ x_3=4\)
  6. Solve the following equations:

    (a)   \(x^2=x+2\)

    (b)   \(x^2=6x\)

    (c)   \(x^3=16x\)

    (d)   \(x^3+45=5x^2+9x\)

    Solutions:    (a)  \(x_1=2,~ x_2=-1\);     (b)  \(x_1=0,~ x_2=6\);     (c)  \(x_1=0,~ x_2=4,~ x_3=-4\);     (d)  \(x_1=5,~ x_2=3,~ x_3=-3\)
  7. Express the chosen variable out of the given equation:

    (a)   \(a^2=b+c,~~~b=?\)

    (b)   \(\frac{\textstyle e+f}{\textstyle g}=h,~~~ g=?\)

    (c)   \(\frac{\textstyle m^2}{\textstyle n+p}=r^3,~~~ p=?\)

    Solutions:    (a)  \(b=a^2-c\);     (b)  \(g=\frac{e+f}{h}\);     (c)  \(p=\frac{m^2}{r^3}-n\)
  8. Express the chosen variable out of the given equation:

    (a)   \(\frac{\textstyle a}{\textstyle b\,c}-d=0,~~~ a=?\)

    (b)   \(\frac{\textstyle a}{\textstyle b\,c}-d=0,~~~ b=?\)

    (c)   \(\frac{\textstyle a}{\textstyle b\,c}-d=0,~~~ c=?\)

    (d)   \(\frac{\textstyle a}{\textstyle b\,c}-d=0,~~~ d=?\)

    Solutions:    (a)  \(a=bcd\);     (b)  \(b=\frac{a}{cd}\);     (c)  \(c=\frac{a}{bd}\);     (d)  \(d=\frac{a}{bc}\)
  9. Solve given equations for variable \(a\):

    (a)   \(v=a\,t,~~~ a=?\)

    (b)   \(s=\frac{1}{2}\,a\,t^2,~~~ a=?\)

    (c)   \(\frac{\textstyle 1}{\textstyle a}+\frac{\textstyle 1}{\textstyle b}=\frac{\textstyle 1}{\textstyle f},~~~ a=?\)

    Solutions:    (a)  \(a=\frac{v}{t}\);     (b)  \(a=\frac{2s}{t^2}\);     (c)  \(a=\frac{bf}{b-f}\)

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