I'm not sure what your variables are, but I will try task 3 with you.
y=$500(in billions)
x= the number of years that have passed since 2009
percentage of decrease: 1 - % =
so your formula will look like this: y(1 - %)^x
Answer:
12 =x
20.78460969=y
Step-by-step explanation:
sin theta = opposite side / hypotenuse
sin 60 = y /24
Multiply each side by 24
24 sin 60 = y/24*24
24 sin 60 =y
20.78460969=y
cos theta = adjacent side / hypotenuse
cos 60 = x /24
Multiply each side by 24
24*cos 60 = x/24*24
24 cos 60=x
12 =x
For the sake of showing work I will replace the empty space with an x like so...

To find out what x is you must cross multiply (aka butterfly)
***Image of this step is attached below
9*x = 10*90
9x = 900
Next divide 9 to both sides to finish isolating x. Since 9 is being multiplied by x, division (the opposite of multiplication) will cancel 9 out (in this case it will make 9 one) from the left side and bring it over to the right side.
9x ÷ 9 = 900 ÷ 9
1x = 100
x = 100
To make these fractions equivalent the empty spot must be 100

Hope this helped!
~Just a girl in love with Shawn Mendes
Answer:
10.5
Step-by-step explanation:
225÷21.50
=10.46511
=10.5(3sf)
Rise is 3 and run is 1 so the slope is 3