I'm not sure what we're being asked to find here but if this is putting the equation into slope-intercept form, then it's:
3x - y = -1
-y = -3x -1
y = 3x - 1
And
-3x + 4y = -14
4y = 3x - 14
y = 0. 75x - 3.5
But if you're asking to solve this as systems of equations then:
3x - y = -1
-3x + 4y = -14
Solving by elimination. Add both equations together.
3x - y = -1
+ -3x + 4y = -14
———————————
3y = -15
Divide both sides by 3.
y = -5
Now that we know the numerical value of y, we can solve for x.
3x - y = -1 -3x + 4y = -14
3x - (-5) = -1 -3x + 4(-5) = -14
3x + 5 = -1 -3x - 20 = -14
3x = -6 -3x = 6
x = -2 x = -2
So, the solution/coordinates to these system of equations are (-2, -5).