+49 Let $f(x)=x^2-7x+18$ and let $g(f(x))=2x+3$. What is the sum of all possible values of $g(8)$?
+33661 Let f(x)=x^2-7x+18 and let g(f(x))=2x+3. What is the sum of all possible values of g(8)?
We have f(x) = 8, so x2 - 7x + 18 = 8 or x2 - 7x + 10 = 0 which factorises as: (x - 2)(x - 5) = 0
Hence x = 2 and x = 5 are two solutions for x
So g(2) = 7 and g(5) = 13 the sum of which is 20.
