How do you multiply (x-9)^2?

2 Answers
Feb 13, 2016

Alternate method.
=x^2-18x+81

Explanation:

We know that
(a-b)^2=a^2-2ab+b^2
In the given question (x-9)^2
a=x and b=9. Substituting the values we obtain
(x-9)^2=x^2-2*x*9+9^2

=>x^2-18x+81

Feb 13, 2016

x^2-18x+81

Explanation:

(x-9)^2

Remember the formula (a+b)^2=a^2+2ab+b^2

In this case a=x,b=-9

And remember -9^2=-9*-9=81

Substitute the values:

We get:

rArrx^2+2(x)(-9)+81

rArr=x^2-18x+81