For this case, the first thing we must do is define a variable.
We have then:
x: unknown number
Doing the multiplication we have:

From here, we clear the value of x.
We have then:

Therefore, we have:
Answer:
7 times 1/7 equals 1
Answer:
m∡A = 100°
m∡B = 50°
m∡C = 30°
Step-by-step explanation:
let 'x' = m∡B; 50°
let '2x' = m∡A; 100°
let 'x-20' = m∡C; 30°
x + 2x + x - 20 = 180
4x - 20 = 180
4x = 200
x = 50