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If the area of a rectangular pool is represented by (12x×x)-17x-5, the length could be represented by ... A.(3x+1) B.(3x+5) C.(4x-5) D.(4x+1)

User Derui Si
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1 Answer

15 votes
15 votes

Answer:

D.(4x+1)

Explanation:

The area of the rectangular pool is given by

Area = length * breadth

Area = (12x×x)-17x-5

A= 12x²- 17x- 5

Factorising the quadratic equation by mid term break rule.

A= 12x²- 20x + 3x- 5

( when we multiply 12 and -5 we get -60 . We need two numbers which when added give -17 and when multiplied give -60. The two numbers would be -20 and +3. The minus has to be with the bigger number as we need - 17.)

A = 4x( 3x- 5) + 1( 3x-5)

(taking commons will evaluate it further.)

A= (3x-5) (4x+1)

so the length could either be 3x-5 or 4x+1

From the given options we have

4x+1 as the length because the rest do not match the factors obtained.

User Oviroa
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