Expresswala Academy Mathematics Tuition

Simple Equations using Integers

Question paper, Set 4

  • Set 4 of 10
  • 20 questions
  • 50 marks
  • 1 hour 30 minutes

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Work each question on paper first, then open its answer and solution to check your work.

  1. If x+74=8x + 74 = 8, then find xx.
    1 mark
    Answer and solution

    x+74=8x + 74 = 8

    ⇒x=8−74\Rightarrow x = 8 - 74

    ⇒x=−66\Rightarrow x = -66

    Answer: x=−66x = -66

  2. Solve x−6=72x - 6 = 72.
    1 mark
    Answer and solution

    x−6=72x - 6 = 72

    ⇒x=72+6\Rightarrow x = 72 + 6

    ⇒x=78\Rightarrow x = 78

    Answer: x=78x = 78

  3. Solve x×4=312x \times 4 = 312.
    1 mark
    Answer and solution

    x×4=312x \times 4 = 312

    ⇒x=3124\displaystyle \Rightarrow x = \frac{312}{4}

    ⇒x=78\Rightarrow x = 78

    Answer: x=78x = 78

  4. Solve x9=78\displaystyle \frac{x}{9} = 78.
    1 mark
    Answer and solution

    x9=78\displaystyle \frac{x}{9} = 78

    ⇒x=78×9\Rightarrow x = 78 \times 9

    ⇒x=702\Rightarrow x = 702

    Answer: x=702x = 702

  5. Solve: (i) x+82=−70x + 82 = -70 (ii) x−64=−57x - 64 = -57 (iii) x×5=195x \times 5 = 195 (iv) x26=834\displaystyle \frac{x}{26} = 834
    5 marks
    Answer and solution

    (i) x+82=−70x + 82 = -70

    ⇒x=−70−82\Rightarrow x = -70 - 82

    ⇒x=−152\Rightarrow x = -152

    (ii) x−64=−57x - 64 = -57

    ⇒x=−57+64\Rightarrow x = -57 + 64

    ⇒x=7\Rightarrow x = 7

    (iii) x×5=195x \times 5 = 195

    ⇒x=1955\displaystyle \Rightarrow x = \frac{195}{5}

    ⇒x=39\Rightarrow x = 39

    (iv) x26=834\displaystyle \frac{x}{26} = 834

    ⇒x=834×26\Rightarrow x = 834 \times 26

    ⇒x=21684\Rightarrow x = 21684

    Answer: (i) x=−152x = -152, (ii) x=7x = 7, (iii) x=39x = 39, (iv) x=21684x = 21684

  6. Find xx if x−581=−803x - 581 = -803.
    1 mark
    Answer and solution

    x−581=−803x - 581 = -803

    ⇒x=−803+581\Rightarrow x = -803 + 581

    Column subtraction: 803−581=222803 - 581 = 222; the bigger number is negative, so xx is negative

    ⇒x=−222\Rightarrow x = -222

    Answer: x=−222x = -222

  7. Find xx if x×13=2665x \times 13 = 2665.
    2 marks
    Answer and solution

    x×13=2665x \times 13 = 2665

    ⇒x=266513\displaystyle \Rightarrow x = \frac{2665}{13}

    Long division: 26÷13=226 \div 13 = 2, remainder 00; 6÷13=06 \div 13 = 0, remainder 66; 65÷13=565 \div 13 = 5, remainder 00

    ⇒x=205\Rightarrow x = 205

    Answer: x=205x = 205

  8. Solve x−3=58\displaystyle \frac{x}{-3} = 58.
    1 mark
    Answer and solution

    x−3=58\displaystyle \frac{x}{-3} = 58

    ⇒x=58×(−3)\Rightarrow x = 58 \times (-3)

    +×−=−+ \times - = -

    ⇒x=−174\Rightarrow x = -174

    Answer: x=−174x = -174

  9. If 4x−81=−1854x - 81 = -185, then find xx.
    2 marks
    Answer and solution

    4x−81=−1854x - 81 = -185

    ⇒4x=−185+81\Rightarrow 4x = -185 + 81

    ⇒4x=−104\Rightarrow 4x = -104

    ⇒x=−1044\displaystyle \Rightarrow x = \frac{-104}{4}

    ⇒x=−26\Rightarrow x = -26

    Answer: x=−26x = -26

  10. If x5−32=65\displaystyle \frac{x}{5} - 32 = 65, then find xx.
    3 marks
    Answer and solution

    x5−32=65\displaystyle \frac{x}{5} - 32 = 65

    ⇒x5=65+32\displaystyle \Rightarrow \frac{x}{5} = 65 + 32

    ⇒x5=97\displaystyle \Rightarrow \frac{x}{5} = 97

    ⇒x=97×5\Rightarrow x = 97 \times 5

    ⇒x=485\Rightarrow x = 485

    Answer: x=485x = 485

  11. Solve: (i) 9x8+24=−30\displaystyle \frac{9x}{8} + 24 = -30 (ii) 5x9−37=−27\displaystyle \frac{5x}{9} - 37 = -27
    5 marks
    Answer and solution

    (i) 9x8+24=−30\displaystyle \frac{9x}{8} + 24 = -30

    ⇒9x8=−30−24\displaystyle \Rightarrow \frac{9x}{8} = -30 - 24

    ⇒9x8=−54\displaystyle \Rightarrow \frac{9x}{8} = -54

    ⇒9x=−54×8\Rightarrow 9x = -54 \times 8

    ⇒9x=−432\Rightarrow 9x = -432

    ⇒x=−4329\displaystyle \Rightarrow x = \frac{-432}{9}

    ⇒x=−48\Rightarrow x = -48

    (ii) 5x9−37=−27\displaystyle \frac{5x}{9} - 37 = -27

    ⇒5x9=−27+37\displaystyle \Rightarrow \frac{5x}{9} = -27 + 37

    ⇒5x9=10\displaystyle \Rightarrow \frac{5x}{9} = 10

    ⇒5x=10×9\Rightarrow 5x = 10 \times 9

    ⇒5x=90\Rightarrow 5x = 90

    ⇒x=905\displaystyle \Rightarrow x = \frac{90}{5}

    ⇒x=18\Rightarrow x = 18

    Answer: (i) x=−48x = -48, (ii) x=18x = 18

  12. Solve x+5=45−xx + 5 = 45 - x.
    2 marks
    Answer and solution

    x+5=45−xx + 5 = 45 - x

    ⇒x+x=45−5\Rightarrow x + x = 45 - 5

    ⇒2x=40\Rightarrow 2x = 40

    ⇒x=402\displaystyle \Rightarrow x = \frac{40}{2}

    ⇒x=20\Rightarrow x = 20

    Answer: x=20x = 20

  13. Solve 7x+25=157−5x7x + 25 = 157 - 5x.
    3 marks
    Answer and solution

    7x+25=157−5x7x + 25 = 157 - 5x

    ⇒7x+5x=157−25\Rightarrow 7x + 5x = 157 - 25

    ⇒12x=132\Rightarrow 12x = 132

    ⇒x=13212\displaystyle \Rightarrow x = \frac{132}{12}

    ⇒x=11\Rightarrow x = 11

    Answer: x=11x = 11

  14. Solve 4x−13+6x=17+5x4x - 13 + 6x = 17 + 5x.
    3 marks
    Answer and solution

    4x−13+6x=17+5x4x - 13 + 6x = 17 + 5x

    ⇒10x−13=17+5x\Rightarrow 10x - 13 = 17 + 5x

    ⇒10x−5x=17+13\Rightarrow 10x - 5x = 17 + 13

    ⇒5x=30\Rightarrow 5x = 30

    ⇒x=305\displaystyle \Rightarrow x = \frac{30}{5}

    ⇒x=6\Rightarrow x = 6

    Answer: x=6x = 6

  15. Find xx if 60−5x=10060 - 5x = 100.
    2 marks
    Answer and solution

    60−5x=10060 - 5x = 100

    ⇒−5x=100−60\Rightarrow -5x = 100 - 60

    ⇒−5x=40\Rightarrow -5x = 40

    ⇒x=40−5\displaystyle \Rightarrow x = \frac{40}{-5}

    (+÷−=−)(+ \div - = -)

    ⇒x=−8\Rightarrow x = -8

    Answer: x=−8x = -8

  16. Solve: (i) 3x+115=189+5x3x + 115 = 189 + 5x (ii) −4x+30−13x=149-4x + 30 - 13x = 149
    5 marks
    Answer and solution

    (i) 3x+115=189+5x3x + 115 = 189 + 5x

    ⇒3x−5x=189−115\Rightarrow 3x - 5x = 189 - 115

    ⇒−2x=74\Rightarrow -2x = 74

    ⇒x=74−2\displaystyle \Rightarrow x = \frac{74}{-2}

    (+÷−=−)(+ \div - = -)

    ⇒x=−37\Rightarrow x = -37

    (ii) −4x+30−13x=149-4x + 30 - 13x = 149

    ⇒−17x+30=149\Rightarrow -17x + 30 = 149

    ⇒−17x=149−30\Rightarrow -17x = 149 - 30

    ⇒−17x=119\Rightarrow -17x = 119

    ⇒x=119−17\displaystyle \Rightarrow x = \frac{119}{-17}

    (+÷−=−)(+ \div - = -)

    ⇒x=−7\Rightarrow x = -7

    Answer: (i) x=−37x = -37, (ii) x=−7x = -7

  17. The sum of two integers is −898-898. If one of them is −319-319, then find the other.
    2 marks
    Answer and solution

    Let the other integer be xx.

    x+(−319)=−898x + (-319) = -898

    ⇒x=−898−(−319)\Rightarrow x = -898 - (-319)

    ⇒x=−898+319\Rightarrow x = -898 + 319

    ⇒x=−579\Rightarrow x = -579

    Answer: −579-579

  18. What number should be added to 229229 to get 194194?
    2 marks
    Answer and solution

    Let the number be xx.

    229+x=194229 + x = 194

    ⇒x=194−229\Rightarrow x = 194 - 229

    ⇒x=−35\Rightarrow x = -35

    Answer: −35-35

  19. What number should be subtracted from −144-144 to get 2525?
    3 marks
    Answer and solution

    Let the number be xx.

    −144−x=25-144 - x = 25

    ⇒−x=25+144\Rightarrow -x = 25 + 144

    ⇒−x=169\Rightarrow -x = 169

    ⇒x=−169\Rightarrow x = -169

    Answer: −169-169

  20. (i) The product of two integers is 19251925. If one of them is −25-25, then find the other. (ii) The difference of two integers is 3333. If the smaller of them is 6464, find the larger.
    5 marks
    Answer and solution

    (i) Let the other integer be xx.

    x×(−25)=1925x \times (-25) = 1925

    ⇒x=1925−25\displaystyle \Rightarrow x = \frac{1925}{-25}

    Long division: 192÷25=7192 \div 25 = 7, remainder 1717; 175÷25=7175 \div 25 = 7, remainder 00

    (+÷−=−)(+ \div - = -)

    ⇒x=−77\Rightarrow x = -77

    (ii) Let the larger integer be xx.

    Larger −- smaller == difference

    x−64=33x - 64 = 33

    ⇒x=33+64\Rightarrow x = 33 + 64

    ⇒x=97\Rightarrow x = 97

    Answer: (i) −77-77, (ii) 9797