m∠FED = m∠JED + m∠FEJ
We have m∠FED = 83°, m∠JED = 3x + 9 and m∠FEJ = 2x + 19. Substitute:
83 = (3x + 9) + (2x + 19)
83 = (3x + 2x) + (9 + 19)
83 = 5x + 28 subtract 28 from both sides
55 = 5x divide both sides by 5
11 = x
