Answer:
25
Explanation:
Since the triangle is equilateral, all the sides have the same measures.
You can set any two sides equal to each other, and solve for x.
4x-30 = 2x + 20
4x = 2x + 50 add 30 to both sides
2x = 50 subtract 2x from both sides
x = 25 divide both sides by 2
You can plug x into the expressions and compare the sides to make sure its correct.