F(x) = x² - 81
Finding f⁻¹(x) the inverse function
Let y = f(x) and solve for x.
y = x² - 81
y + 81 = x²
x² = y + 81
x = √(y + 81)
Recall f(x) = y, that means x = f⁻¹(y)
x = √(y + 81)
f⁻¹(y) = √(y + 81)
Therefore f⁻¹(x) = √(x + 81)
-90 -45 -30 -18 -15 -10 -6 -5 -3 -2 -1
Whats the question?
I think the question is "how much are 7 of them if the sale wasn't going on."
which, without the sale, each cookie is originally $1.5, multiplied by 7, is $10.5 so you save a lot of money.
i think this was your question
