Help me with my math?

Question

7x+8y if x=7 and y=8


x^2 -5y if x=4 and y=5

4x^3 -5+2y if x=3 and y=4

Answer 1

It appears that all you have to do is replace(substitute) the letters x and y with numbers that are given to you.

 

"PLUG AND CHUG!"

 

I'll do one for you and then you can do the other: 7x+8y if x=7 and y=8 means

7(7) + 8(8) = 49 + 64 = 113.