The correct answer is A, 50, 50, 50.
This is an equilateral triangle, meaning all sides are the same thing.
We can tell by the dash mark on each side, which identifies each side as being the same length.
Because of this, we know all three will be the same length.
4x + 2 = 5x - 10
Subtract 4x from both sides.
2 = x - 10
Add 10 to both sides.
12 = x
The value of x is 12. We can plug this value in to each expression to find each side length.
4(12) + 2
48 + 2 = 50
5(12) - 10
60 - 10 = 50
3(12) + 14
36 + 14 = 50