Answer:
m<ABC = 45
m<DBC = 34°
Explanation:
Given:
m<ABD = 79°
m<ABC = (8x - 3)°
m<DBC = (5x + 4)°
Step 1: Generate an equation to find the value of x
m<ABC + m<DBC = m<ABD (angle addition postulate)
(8x - 3) + (5x + 4) = 79
Solve for x
8x - 3 + 5x + 4 = 79
13x + 1 = 79
Subtract 1 from both sides
13x + 1 - 1 = 79 - 1
13x = 78
Divide both sides by 13
x = 6
Step 2: find m<ABC and m<DBC by plugging the value of x into the expression of each angle
m<ABC = (8x - 3)°
m<ABC = 8(6) - 3 = 48 - 3 = 45°
m<DBC = (5x + 4)°
m<DBC = 5(6) + 4 = 30 + 4 = 34°