A ladder is leaning against a building so that the distance from the ground to the top of the latter is 9 feet less than the length of the ladder. Find the length of the latter is the distance from the bottom of the ladder in to the building is 21 feet

a

step-by-step explanation:

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.