Remember the formula for calculating volume is: Volume = Area by height. V = A X h.
For a triangle the area is calculated using the formula: Area = half of base by altitude. A = 0.5 X b X a.
So to calculate the volume of a triangular prism, the formula is: V = 0.5 X b X a X h
0.5s + 1 = 7 + 4.5s Subtract 4.5s from both sides
-4s + 1 = 7 Subtract 1 from both sides
-4s = 6 Divide both sides by -4
s = -

Simplify
s = -
The answer for this question is letter B