Question 552447
cost for supplies equals 5x^2 - 3x + 1
cost for utilities equals x - 9
total cost equals cost for supplies plus cost for utilities.
this equals 5x^2 - 3x + 1 + (x - 9) which equals:
5x^2 -3x + 1 + x - 9 which equals:
5x^2 - 2x - 8
if we assume that x = 30, then we get the following:
costs for supplies = 5(30)^2 - 3(30) + 1
costs for utilities = 30 - 9
total costs equals 5(30)^2 - 2(30) - 8
lets see how that works out.
costs for supplies = 4411
costs for utilities = 21
total costs = 4432
since 4411 + 21 = 4432, the formula for total costs is good.