What is the factored form of 4x2 + 23x – 72?

(x + 8 )(4x - 9)

using the a-c method

consider the factors of the product 4 × - 72 = - 288 which sum to + 23

The factors are + 32 and - 9

split the middle term using these factors

4x² + 32x - 9x - 72 ( factor by grouping )

= 4x( x + 8) - 9( x + 8)

take out the common factor ( x + 8)

= (x + 8 )(4x - 9 )

step-by-step explanation:

no, her answer is not correct.   we square the lengths of all sides and then determine whether the pythagorean theorem holds here:

9² + 15² = 306.   this is not equal to the square of the longest side ( that square being 395.   answer c is correct.