Equation 1) y = 3x
Equation 2) y = 7x + 16
For both equations, move x to the left side, so that x and y are on the same side. To do so, subtract 3x from equation 1, and subtract 7x from equation 2.
So now, we have :
1) - 3x + y = 0
2) -7x + y = 16
Subtract equations from each other.
4x = -16
Divide both sides by 4.
x = -4
Plug in -4 for x in first equation.
y = 3x
y = 3(-4)
y = -12
(-4, -12)
~Hope I helped!~