(a,1)(a,2)(a,3)(a,4)(b,1)(b,2)(b,3)(b,4)
Answer:
13x-10y
Step-by-step explanation:
Combine like terms;
10x+3x = 13x
-8y-2y = -10y
So it would give the equation of 13x-10y
4x + 89.95 = 628.35 <== ur equation
4x = 628.35 - 89.95
4x = 538.40
x = 538.40 / 4
x = 134.60 <== the cost for each cavity filling
