Answer:
Because a straight line = 180, we can find x like this :
(5x - 20) + (3x - 40) = 180
Step 1 - collect like terms
8x - 60 = 180
Step 2 - Move terms around to isolate x
8x = 180 + 60
Step 3 - Divide both sides by 8
x = 30
Now you can find the value of the angles by plugging in x
∠f = (5 x 30) - 20
= 130 degrees
∠g = (3 x 30) - 40
= 50 degrees
We can check to see if this works by adding them up
130 + 50 = 180, so this is correct
Hope this helps! I would really appreciate a brainliest if possible :)