Subject: algebra II Name: Oryan Who are you: Student HELP!!! I just don't get it! How do I even go about starting to figure this out! Given f(x)=-2x^3 and g(x)-4x-5, find g(f(-1)) Hi Oryan. I'll show you how to solve this with a similar question: f(x) = 3x2-7 g(x) = 5+8x-1 Find g(f(-1)). Remember BEDMAS from elementary school? It says do what's in the brackets first, so g(f(-1)) becomes first a question of what is f(-1)? Plug it in: f(-1) = 3(-1)2 - 7 = 3 - 7 = -4. Now replace f(-1) with -4: g(f(-1)) = g(-4). So what is g(-4)? Substitute -4 for x in the expression for g(x): g(-4) = 5 + 8(-4)-1 = 5 - 8/4 = 3. There is slightly different approach as well: in g(x) = 5 + 8x-1 we are saying that whatever is between the parentheses on the left hand side replaces x on the right hand side. This means g(f(x)) = 5+ 8(f(x))-1. But we can substitute for f(x) now on the right hand side: So g(f(x)) = 5 + 8(3x2-7)-1 = 5 + 8 / (3x2 - 7). And now to solve g(f(-1)) you can substitute -1 for x: g(f(-1) = 5 + 8 / (3(-1)2 - 7) = 5 + 8 / (3 - 7) = 5 + 8 / (-4) = 3. Hope this helps, Stephen La Rocque.