Answer:
Step-by-step explanation:
3*(4x - 3) = 63 Divide both sides by 3
4x - 3 = 63/3
4x - 3 = 21 Add 3 to both sides
4x = 21 + 3
4x = 24 Divide by 4 on both sides
4x/4 = 24/4
x = 6
Note: The perimeter is the sum of all three sides. One side is 4x - 3 All 3 sides must be 3*(4x - 3)