Which function has an inverse that is a function

Given: x + y = 6. if xe (-15, -6, -1), then which of the following sets of ordered pairs are solutions? © {(-15, -21), (-6, -12), (-1, -7)} [(-15, 21), (-6, , 7)} {(-15, 21), (-6, 12), (-1, -7)}

Solve the equation x/4 - 5= -8 -27 -12 -7 12

Can someone check if i did this correct. it’s number 4 if you’re wondering.