If f(x) = -7x + 5x2 + 10, what does f(-2) equal?

All you have to do is replace x in the function with the number given. Remember that with f(x), (x) is the input and the equation is the "machine" that does something with the input, and then f(x), which is equal to the "machine", is your output so you can also say that f(x) is the same as y. So for the machine f(x)=3x^2+5x-2, if you input -2, you have: y=3(-2)^2+5(-2)-2 and then multiply:
y=3(-2)^2+5(-2)-2 Exponents are always first:
y=3(4)+5(-2)-2 Now multiply
y=12-10-2 subtract
y=0

F(x) = -7x + 5x^2 + 10
f(x) = -7(-2) + 5(-2)^2 + 10
f(x) = 14 + 5(4) + 10
f(x) = 14 + 20 + 10
f(x) = 44