A painter charges $15.30 per hour, plus an additional amount for the supplies. If he made $187.81 on a job where he worked 7 hours, how much did the supplies cost?

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8