Question

Find the expression of equivalent to (x-1)(x-9)

Answer 1

(x-1)(x-9)
=x^2 -9x -x + 9
=x^2 -10x + 9

Answer 2

Foil aka distribute

FOIL
First
Outer
Inner
Last

First: x times x=x²
Outer: x times x times -9=-9x
Inner: -1 times x=-1x
last: -1 times -9=9
add them

x²-9x-1x+9=
x²-10x+9