Question

Using technology, we determined that Mary’s investment account can be modeled by the function, M(x) = 4.96(2.18)x in thousands of dollars. What was Mary’s initial investment?

Answer 1

well, her initial investment happened at day 0, namely x = 0, let's check,


`\bf M(x)= 4.96(2.18)^x\qquad \boxed{x=0}\qquad M(0)= 4.96(2.18)^0 \\\\\\ M(0)= 4.96(1)\implies M(0)=4.96`

Answer 2

$4960.

Explanation:

We have been given that Mary’s investment account can be modeled by the function,
`M(x)=4.96(2.18)^x` in thousands of dollars. We are asked to find Mary's initial investment.

We can see that the given function is an exponential function where, initial value is 4.96 and growth factor is 2.18.

Since the function given Mary's investment in thousands of dollars, so we need to multiply 4.96 by $1000.

`\text{Mary's initial investment}=4.96* \$1000`

`\text{Mary's initial investment}=\$4960`

Therefore, Mary's initial investment was $4960.