Complete the algebraic expression. I'm having trouble understanding how to do this, could use some help.

Complete the solution of the equation. find the value of y when x equals to 6 4x+y=20

Ineed on this question me get the answer

Carl is hanging pictures in his home. there is a space on a wall that has a width of 4 feet. carl has pictures with different widths. which picture width would fit in the space on the wall? a. 46 inches b. 60 inches c. 50 inches d. 54 inches