FOIL
Let’s use a random equation
(3x-7)(6x+2)
the F stands for “first”... the 3x is first in its parenthesis. The 6x is the first in its parenthesis. So multiply those. You get 18x^2
The O stand for “outer” the 3x and 2 are the outer. They equal 6x.
the I stand for “inner”. -7 and 6x are the inner parts of the equation. They equal -42x
The L stand for last. The last are -7 and 2. They equal-14.
Put it all together
18x^2+6x-42x-14
18x^2-36x-14