So you have to plug in the amount to the cost making you problem look like this:
0.85(30)+2.5(2)
25.5+5=30.5
Answer:
6
Step-by-step explanation:
The expression can be rearranged to ...
b = 3 -9/(a+5)
In order for b to be an integer, (a+5) must be an integer divisor of 9. There are exactly 6 of those: ±1, ±3, ±9.
The attached table shows the values (a, b) = (x₁, f(x₁)).