Im trying to study for my final in about 2 days. I have this problem to see if lines are paralell,perpendicular or neither.

9x+3y=12

21x+7y=31

for 9x+3y=12 I got y=-3x+4

I dont know how to solve the other on besides having a fraction like y=-2x+31/7

Please if you can help me on that.

Thank you!

Find the domain of the function

Also g(x)= (5/x+14) The equation is 5 over "x" and 14

Graph the linear function

f(x)=( -7/9x) +6