(-1/3)+3/8 need to solve step by step

I’m stuck on this i don’t understand.

What is the area of triangle pqr on the grid? a triangle pqr is shown on a grid. the vertex p is on ordered pair 7 and 6, vertex q is on ordered pair 1 and 6, and the vertex r is on ordered pair 4 and 2. 5 square units 6 square units 10 square units 12 square units

Which expression is equivalent to (9x - 3 1/ + 1 3/8)