What is 7/8- 3/4 subtracting unlike denominators

Solve by any method (graphing, substitution or linear combination)y = x - 82x + 3y = 1a) (2, -6)b) (5, -3)c) (4, -4)d) (0, -8)i figured it out. the answer is (5, -3)

An air conditioning system can circulate 350 cubic feet of air per minute. how many cubic yards of air can it circulate per minute?

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?