Answer:
While x = -7 and y = 4, x² - 3xy = 133.
Step-by-step explanation:
x² - 3xy
Substitute variables.
(-7)² - 3(-7)(4)
Square -7 remembering that (-x)² = x².
49 - 3(-7)(4)
Multiply -7 and 4.
49 - 3(-28)
Multiply -3 and -28.
49 + 84
Add 49 and 84.
133
First let's solve for the rate, "b", by setting up a ratio with the two points given:
16.875/7.5=(ar^3)/(ar)
2.25=r^2
r=1.5
Now we need to solve for the initial value a using either point given...
7.5=a(1.5)^1
7.5=1.5a
a=5
So now we have solved for both variables and have a complete equation:
y=5(1.5)^x
The correct answer is (D).
Step-by-step explanation:
