# How do you find the y intercept of an exponential function q(x) = -7^(x-4) -1?

May 16, 2016

The y intercept of ANY function is found by setting $x = 0$.
For this function is the y intercept is
$q \left(0\right) = - \frac{1}{7} ^ 4 - 1 = - \frac{2402}{2401} = 1.00041649313$

#### Explanation:

The y intercept of ANY two variable function is found by setting $x = 0$.

We have the function
$q \left(x\right) = - {7}^{x - 4} - 1$
So we set x=0
${y}_{i n t} = q \left(0\right) = - {7}^{0 - 4} - 1$
$= - {7}^{- 4} - 1$
flipping the negative exponent upside down we have
$= - \frac{1}{7} ^ \left(4\right) - 1$
Now we just play with the fractions to get the correct answer.
$- \frac{1}{2401} - 1 = - \frac{1}{2401} - \frac{2401}{2401} = - \frac{2402}{2401} = 1.00041649313$