SINCE THATS AN ISOSCELES TRIANGLE:
AB=BC
SO 3x-4=5x-10
But we have to find x
3x-4=5x-10
Minus 3x on both sides
-4=2x-10
Add 10 on both sides
6=2x
Divide 2 on both sides
3=x
So x is 3
Now since we are looking for side AB which is 3x-4
Substitute in 3 as x
3(3)-4
9-4=5
So 5 is the answer.
Brainlist would be much appreciated!