Find the value of  42-42-42......∞ from Mathemat

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 Multiple Choice QuestionsMultiple Choice Questions

21.

When doing exponents, the work observed in a learner's notebook was as follows

43 x 42 = 45 , 6x 64 = 68 , 73 x 37 = 2110

The learner has not understood how to

  • add exponents and multiply

  • multiply numbers with same base

  • multiply numbers with different bases

  • add exponents


22.

The least number which is a perfect square and is also divisible by 10, 12, 15 and 18 is

  • 1600

  • 900

  • 3600

  • 2500


23.

4-(2-9)0+32÷1+3

  • 15

  • 12

  • 17

  • 16


24.

Given the numbers 3.75 X 10-7334 X 10-7, 375 X 10-9, and 38 X 10-7. Which of these is not equal to 0.000000375?

  • 375 X 10-7

  • 38 X 10-7

  • 3.75 X 10-7

  • 334 X 10-7


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25.

When the number 398 is divided by 5, the remainder is

  • 3

  • 1

  • 4

  • 2


26.

Which of the fractions is the least?

  • 99100

  • 6869

  • 2425

  • 1011


27.

The remainder obtained when 231 is divided by 5

  • 1

  • 2

  • 3

  • 4


28.

If means x, x means +, + means + and + means -, then find the value of 14 - 10 x 4 + 16 + 8

  • 6

  • 142

  • 134

  • 2


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29.

Simplify 3÷8-5÷4-2÷2+813

  • 1317

  • 1713

  • 6813

  • 1368


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30.

Find the value of  42-42-42......

  • 3

  • 6

  • 7

  • 14


B.

6

Let x = 42-42-42........

Squaring on both sides 

x2 = 42 - x 
x2+x-42=0
x2+7x-6x-42=0
x(x+7)-6(x+7)=0
(x-6)(x+7)=0
x=6 and x=-7
Hence x=6 since x =-7 (not possible )


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