What’s the answer for x-3=6

The vertices of a triangle are a(7,5), b(4,2), c(9,2). what is m

Adj has a total of 1075 dance and rock songs on her system. the dance selection is 4 times the size of the rock selection. write a system of equations to represent the situation.

Find the solution of this system of equation -7x+y=-20 9x-3y=36