
therefore, sin(x) = cos(90° - x).
Y=2/3x-7/3
Hope this helps
let's say is "x", thus "x" is the 100%.
we know that 66 is 150%, what is "x"?

Find an x value and f(x) is just it's y value. we can start with x=0
when x=0 y= -3
when x= 2 y= -2
and so on, choose easy to read numbers.
you can finish the rest, let me know if you wanna check your answers or if you are stuck.