21 not sure but you can do it
The answer is c because the variable behind the number s are equal
Multiply the cost by 1.2 (120%) to add 20% tip, and then multiply by 0.85 (85%) to take off 15%
78.96 x 1.2 x 0.85 = 80.54
Y=3
to solve this you just substitute 4 in for x into the equation and solve for y. since negative 3 plus 7 is 4, y=4
416.25
375*.11=41.25
41.25+375=416.25
