Looking at the letters for both triangles B and E are both the middle letters. This means that both those angles would be identical.
Set the two equations to equal each other and solve for x.
x + 15 = 6x - 65
Add 65 to each side:
x + 80 = 6x
Subtract 1 x from each side:
80 = 5x
Divide both sides by 5:
x = 80 /5
x = 16
