Solve for d.
6(d+1)−2d=54
enter your answer in the box.

Explanation:

When x = 0, we have y = 18. The y intercept value is 18. This is the initial value, and it's the value of 'a' in the equation below

y = a*b^x

The value of b is tied to the growth or decay rate, depending on if b > 1 or if 0 < b < 1 respectively.

In this case, we have growth due to y increasing as x increases. They increase together.

When x increases by 1 like this, the value of b can be determined by dividing any y term over its previous value. So for instance, we can say b = 21.6/18 = 1.2 or we could say b = 25.92/21.6 = 1.2

Then note how 1.2 = 6/5, which means b = 6/5

Therefore, y = a*b^x becomes y = 18(6/5)^x

We can confirm this equation by plugging in x values from the table and we should get the y values, or f(x) values, listed

Example: plug in x = 0 to find that

y = 18(6/5)^x

y = 18(6/5)^0

y = 18(1)

y = 18 which matches

Then try x = 1

y = 18(6/5)^x

y = 18(6/5)^1

y = 18(1.2)

y = 21.6 that also matches

I'll let you confirm the other x values.