Answer:
x = 20
<f = 80
<g =100
Explanation:
<f and <g are supplementary so they add to 180
5x-20 + 3x+40 = 180
Combine like terms
8x+20 = 180
Subtract 20 from each side
8x+20-20 = 180-20
8x = 160
Divide by 8
8x/8 = 160/8
x = 20
<f = 5x-20 = 5*20 -20 = 100-20 = 80
<g = 3x+40 = 3*20 +40 = 60+40 = 100