Complementary angles are those angles whose sum is 90 degree.
The measurement of two complementary angles are

There sum have to be 90 degree. That is

Combining like terms ,

Moving 20 to right side

Dividing both sides by 5

So the measurement of the angles are

Given:
and
.
To find:
The value of f(5).
Solution:
We have,

For
,




For
,




For
,




For
,




Therefore, the value of
is
.
So to solve for y, we need to get y alone on one side of the equation. So we are going to subtract 9x from both sides of the equation to get:

And since y is negative, we are going to divide both sides by -1 in order to make the y positive:

First you add up all the items and the coupon then you will get $24.51. then subtract $50.00 take away $24.51 then you will get $25.49. So when she left the store she had $25.49
(2,1)
I first used substitution to get my answer and then used graphing to check. You can easily get a graphing equation by rearranging the second equation.<span />