To solve these you have to plug in the numbers into the equations. For example take the question g(9) + f(4). To solve this you have to think that the number 9 replaces the letter x in the g(x) equation and the number 4 replaces the letter x in the f(x) equation.
Once you plug in the numbers, you can solve each equation separately. You’ll see that g(9) is equal to 757 and f(4) is equal to 51.
Now since the question is asking for g(9)+f(4) you can now do 757+51 which is equal to 808.
I hope I got all the numbers right, but if I didn’t you get the point.