Given the formula / = prt, which shows an equation solving for r?

you are saying it as if a fact, not a question, but yes, you would be correct? ; )

step-by-step explanation:

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225

i think that you should ask google for the answer to that problem because if we don't know it google does

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.