Here are two functions:$$\begin{array}{ccc} f(x) & = & 3x^2-2x+ 4\\ g(x) & = & x^2-kx-6 \end{array}$$If $f(10) - g(10) = 10,$ what is the value of $k?$
Subtract functions: f(x) - g(x) = (3x^2 - 2x + 4) - (x^2 - kx - 6) = 2x^2 - (k + 2) x + 10
Plug in x = 10: f(10) - g(10) = 200 - 10(k + 2) + 10 = 10
Solve for k: k = 8
+11 
