Solve the system of equations.
5y - 4x = -7
2y + 4r = 14

it has to have an angle of 90 degrees

this equation is in point-slope form.

where,

using this equation you can gather a point and the slope, which gives you enough information to draw a line. transform the equation to standard form to start.

the equation is now in standard form, we have a point, as well as the slope:

point: (0, -6)

slope: -2

plot (0,-6), then simply rise/run with the provided slope of -2, once you feel you have a comfortable amount of points - draw a line.