Question

Please can anybody help me with this: Show that (x − 9)(x − 1) ≡ x^2 − 10x + 9

Answer 1

        We will expand the factored form of (x − 9)(x − 1) into the same form as x² − 10x + 9 to show they are equal.

Distribute and multipy out:

(x − 9)(x − 1)

x * x = x²

x * -1 = -x

x * -9 = -9x

-9 * -1 = 9

Add together:

x² +  -x + -9x + 9

x² − 10x + 9

Use the Reflexive property:

x² − 10x + 9 = x² − 10x + 9 ✓