80,292 views
8 votes
8 votes
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
by
3.4k points

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
by
3.0k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.