Find lengths of all altitudes of the triangle whose vertices are (0, 0), (3, 0), and (1, 4)

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.

if you was gonna solve for a, a is a   < -12

- (2, -7)

- lines r and s and lines t and u must be parallel