How would u write this equation?

Answer:
Step-by-step explanation:
y=a*b^x
pass thro' (1, 7.5) n (3, 16.875)
at x=1, y=a*b=7.5
at x=3, y=a^b^3=16.875
dividing, a*b^3/a*b=16.875/7.5
b^2=2.25
b=+1.5 or -1.5
a=7.5/b
a=5 or -5
y=5*(1.5)^x
or
y=(-5)*(-1.5)^x
Answer:
y=5x1.5^x or y=-5x(-1.5)^x
Step-by-step explanation:
Given y=axb^x and it passes through (1, 7.5) n (3, 16.875)
7.5=axb
so a=7.5/b
16.875=axb^3
substitute a into the equation
16.875=7.5/bxb^3
16.876/7.5=b^3/b
2.25=b^2
b=+/-1.5
a=7.5/b
=+/-5
y=5x1.5^x or y=-5x(-1.5)^x