Answer
$6+6-4+8+8+8-1 = 31$
Work Step by Step
On the first two plays gained Marquette 6 yards each time, making the expression:
$6+6$
The next play lost him 4 yards, making it:
$6+6-4$
The next three plays gained him 8 yards each, making the expression:
$6+6-4+8+8+8$
The final play lost him 1 yard, making the final expression:
$6+6-4+8+8+8-1$
This can be simplified:
$(6+6)-4+(8+8+8)-1$
$=12-4+(8+8+8)-1$
$=8+8+8+8-1$
$=32-1$
$=31$
