5x + 20 = 90 - a = 90 - (3x + 40)
5x + 20 = 90 - 3x - 40 = 50 - 3x
5x + 3x = 50 - 20
8x = 30
x = 30/8 = 15/4
b = 3(15/4) + 40 = 45/4 + 40 = 51.25
The measure of a supplementary angle is 180 - 51.25 = 128.75
Answer & Step-by-step explanation:
To find if they have a constant of proportionality of 12, use the following:

Divide y by the x value (x,y), and if the remaining equation is true, then that table has a constant of proportionality of 12.*
:Done
*Make sure you check all the values in a table. Sometimes only the first values will have k=12, while the others don't.
**The constant of proportionality is represented by <em>k</em>.
Step-by-step explanation:
f(5) = 2(5) = 10
hope this helps
I would have to say 32,4 but i would double check it