Question

I am confused on this one

Answer 1

X=3
to find x, it said both equations are equal, so put them equal to each other.
3x + 24 = 4x + 21
-3x -3x

24 = x + 21
-21 -21

3 = x

Answer 2

If a triangle is equilateral then all three sides of equal length.
Therefore:

`4x+21=3x+24\ \ \ \ |-21\\\\4x=3x+3\ \ \ \ |-3x\\\\\boxed{x=3\ units}`