Please help me i need help with this

Franco wants to double the volume of the cone. what should he do?

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)

Can any one me with the answers to these questions asap?