How do you use the FOIL method if there is only one set of parenthesis...

Question

Because you use distributive property with 2 sets

Answer 1

The FOIL "method" refers specifically to the multiplication of two binomials

e.g. (2x+3)(4x-1)
F : first times first -- 8x^2
O : the outsiders -- -2x
I : insiders -- 12x
L : the lasts -- -3

when you have a monomial times a binomial

e.g.
3x(2x+5y)
just use the distributive property
= 6x^2 + 15xy

in effect you are using the distributive property when you are doing the FOIL thing

(2x+3)(4x-1)
= 2x(4x - 1) + 3(4x - 1)
= 8x^2 - 2x + 12x - 3
= ...