Question

Another question from a test. thanks for the help...Find the value of Q in the system so that the solution to the system is
{(x,y) : x-3y=4}

x-3y=4
2x+Qy=8

Answer 1

notice that if we multiply the top equation by 2, then we have 2 equations of the same line iff Q = -6

Answer 2

and we need the second equation to have the same solution set, so it needs to be the same line.