LIKE WHAT TO DO< HOW ITS DONE AND ETC....

FOIL stands for First Outer Inner Last. It is used to multiply 2 binomials

For example (x+4)(x-1)

F(irst) (take the first term of each binomials and multiply them) - (x)*(x) = x^{2}

O(uter) (take the outer term of each binomials and multiply them) - (x)*(-1) = -1x

I(nner) (take the inner term of each binomials and multiply them) - (4)*(x) = 4x

L(ast) (take the last term of each binomials and multiply them) - (4)*(-1) = -4

Then add them all together -> x^{2}-x+4x-4

Combine like terms -> x^{2}+3x-4