Question

Find the product by using identity
2) (x-4)(x+5)​

Answer 1

Answer:

$(x - 4)(x + 5) \\ = x ^{2} - 4x + 5x - 20 \\ = x {}^{2} + x - 20 \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

Answer 2

(x-4)(x+5)

Using the iedntity: (x-a)(x+b) = x² + (-a + b) + (-ab)

= x² + (-4+5) + (-4×5)

= x² + 1 - 20

= x² - 19