Identity property of multiplication
M∠ADB + m∠BDC = m∠ADC [<span>angle addition postulate]
x + x + 10 = 60
2x + 10 = 60
2x = 60 - 10
2x = 50
x = 50/2
x = 25
a
m</span>∠ADB = x = 25°
b
m∠BDC = x + 10 = 25 + 10 = 35°
One solution ! Which is x=-3
15<span>√2 is what I got for the answer.</span>