Michael had 20 dollars to spend on 3 gifts. He spent 11 3/4 dollars on gift A and 3 1/2 dollars on gift B. How much money did he have left for gift C?

square pyramid

step-by-step explanation:

square prism looks like nothing like that

triangular prism has a rectangular base instead of a square base

tetrahedron has a triangular base

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.