Jina has 18 cars available to rent. Let C be the number of cars she would have left after renting R of them.
Write an equation relating C to R. Then use this equation to find the number of cars she would have left after renting 12 of them.
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x=30

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.