In the diagram of ABC below, AB is extended to point D.с(3x + 10)(x + 40°|(x)"BADIf mZCAB = x + 40, mZACB = 3x + 10, mZCBD = 6x, what is mZCAB?

m∠CAB = 65°
Explanation:m∠CAB = x + 40, m∠ACB = 3x + 10, m∠CBD = 6x
∠C + ∠A + ∠B = 180 degrees (sum of angles in a triangle)
∠CAB + ∠CBD = 180 degrees (angles on a straight line)
∠CAB = 180 - ∠CBD
∠CAB = 180 - 6x
m∠CAB + m∠ACB + ∠CAB = 180
x + 40 + 3x + 10 + 180 - 6x = 180
collect like terms:
x + 3x - 6x + 40 + 10 + 180 = 180
-2x + 230 = 180
-2x = 180 -230
-2x = -50
Divide both sides by -2:
-2x/-2 = -50/-2
x = 25
m∠CAB = x + 40 = 25 + 40
m∠CAB = 65°