Answer: -5
Step-by-step explanation:
Multilpy 
x (-5 + 5 x (3)
Calculate x (-5 - 15)
- x 20
= -5
Answer:
10(3)^x
Step-by-step explanation:
The function contains the points (2,90) and (4,810). Use the general form y=abx to write two equations:
90=ab^2 and 810=ab^4
Solve each equation for a:
a=90/b^2 and a=810/b^4
Since a=a, set the other sides of the equations equal and solve for b.
90/b2=810/b4
Cross multiply, then divide and simplify as follows:
90b^4=810b^2
b^4/b^2=810/90
b^2=90
b^3
Now, use the value of b and the point (2,90) to find the value of a.
90=a(3^2)
a=10
So, substitute answers in original equation for a final answer of f(x)=10(3)^x.
