Find the following product: (y-10)^2

Answer 1

Write down as:
(y-10)^2
= (y-10)*(y-10)
and apply the FOIL rule, or
= y^2 -10y -10y +100
= y^2 -20y + 100

Alternatively, memorize the rule:
(a+b)²
=a²+2ab+b²
substitute y for a, and -10 for b.