Answer:
(x + 3)(5x + 2) , (2x - 1)(3x + 5)
Explanation:
given
A = 5x² + 12x + 6
consider the factors of the product of the x² term and the constant term which sum to give the coefficient of the x- term
product = 5 × 6 = 30 and sum = 17
the factors are + 15 and + 2
use these factors to split the x- term
5x² + 15x + 2x + 6 ( factor the first/second and third/fourth terms )
= 5x(x + 3) + 2(x + 3) ← factor out (x + 3) from each term
= (x + 3)(5x + 2)
then
length = x + 3 , breadth = 5x + 2 or indeed the other way round
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given
A = 6x² + 7x - 5
consider the factors of the product of the coefficient of the x² term and the constant term which sum to give the coefficient of the x- term
product = 6 × - 5 = - 30 and sum = + 7
the factors are - 3 and + 10
use these factors to split the x- term
6x² - 3x + 10x - 5 ( factor the first/second and third/fourth terms )
= 3x(2x - 1) + 5(2x - 1) ← factor out (2x - 1) from each term
= (2x - 1()3x + 5)
then
length = 2x - 1 , breadth = 3x + 5 or the other way round