Question

Jen factored x² - 4x - 21 as (x - 3)(x + 7) What did she do wrong?

Answer 1

Jen should have done (x+3)(x-7) bc the middle value of the original equation needs to be equal to the two numerical values added together from the factored equation

Answer 2

She didn't put the sign's in the proper place, it should be ( x + 3 ) ( x - 7 )

Explanation:

( x - 3 ) ( x + 7 ) = x² + 7x - 3x - 21 = x² + 4x - 21

( x + 3 ) ( x - 7 ) = x² - 7x + 3x - 21 = x² - 4x - 21