6c=18 how do you solve this equation

Solve with work both bert and ernie received an increase in their weekly salaries. bert's salary increased from $520 to $520. ernie's salary went from $580 to $645. find the percent of increase for each salary. what was the larger of the two percents ?

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Find the solution(s) to the system of equations. select all that apply y=x^2-1 y=2x-2