reginacperkins reginacperkins 23-10-2017 Mathematics contestada The cost of a plumbing repair is given by the equation y=45x+30, where x is the number of hours the repair takes and y is the total cost in dollars.if a repair costs a total of $300 how manny hours did it take? Select the correct answer below. A.6 B.7 C. 7 1/3 D.10