Question

Write an exponential function y=ab^x whose graph passes through (1,6) and (3,54)

Answer 1

`y=ab^x\\\\(1;\ 6)\to x=1;\ y=6\\(3;\ 54)\to x=3;\ y=54\\\\\text{substitute the values of x and y to the equation}\\\\ \left\{\begin{array}{ccc}6=ab^1&\to&a=(6)/(b)^((*))\\54=ab^3\end{array}\right\\\\\text{substitute (*) to the second equation}\\\\54=(6)/(b)\cdot b^3\\\\54=6\cdot b^2\ \ \ \ |:6\\\\b=9\to b=\sqrt9\to b=3 \\\\\text{substitute the value of b to the (*)}\\\\a=(6)/(3)=2\\\\\text{Answer:}\ y=2\cdot3^x`