When we have a function such as h(x) = 2x, and we want to find the value of h at a given x value, we plug in the given number for x. For example, h(3) = 2*3 = 6.
We do the same thing with g(f(7)). In this case we plug 7 into f(x) for x, then plug the result of f(7) into g(x) for x.
f(7) = 15*7 - 12 = 93
g(93) = -15*93^2 + 14*93 - 10 = -128443
If u multiply the first equation by -4, u get -2x - y = -20
and when u add the 2 equations..
-2x - y = -20
2x + 3/8y = 5
-----------------
0 - 5/8y = -15.....u notice that the x terms r eliminated.
I hope this helps you
(f+g)(x)=2x+1+x^2-7
(f+g)(z)=x^2+2x-6
