Y=ab^x (-3,7) (2,4)

Question

Trying to figure out how to solve. I get to

7=ab^-3

4=ab^2

solve both for a

7/b^-3 =a and 4/b^2 =a therefore

7/b^-3=4/b^2

7b^2=4b^-3

need to divide both sides by b^2 but not sure what to do with the negative exponent

Answer 1

y = A*b^x

7 = A*b^(-3)

7b^3 = a*b^(-3)*b^3 <--- multiplies both sides by b^3

7b^3 = a <--- b cancels out

4 = A*b^2

4 = (7b^3)*b^2

4 = 7b^5

(4/7) = b^5

b = (4/5)^(1/5)

a = 7*[(4/5)^(1/5)]^3

= 7*[ (4/5)^(3/5)]

y = 7*(4/5)^(3/5) * (4/5)^(1/5)^x