Answer:
7 yards
Step-by-step explanation:
gained 6 yards on a first down +6
lost 15 yards on the second down - 15
gained 12 yards on the third down +12
At the end of the third down
+6 -15+12 = +3
They want to have a 10 yard gain at the end of the 4th down
+3 + x = +10
Subtract 3 from each side
+3-3 +x = +10-3
x = 7
They need to gain 7 yards
