Step-by-step explanation:
-9x + 1 = -x + 17
collect like terms
-9x + x = 17-1
-8x = 16
divide both sides by -8
-8x/-8 = 16/8
x = 2
Answer:
-3 +2 +-1 +-2 +-3 +1 = -6 yards total
-6 / 6 = -1 yard per play average