bantuin jawab ya:) plissss

dbc = 180 - (4x + 20) = 180 - 4x - 20 = 160 - 4x
bdc = 180 - (4x - 5) = 180 - 4x + 5 = 185 - 4x

bdc + dbc + bcd = 180
185 - 4x + 160 - 4x + 35 = 180
380 - 8x = 180
380 - 180 = 8x
200 = 8x
x = 200/8 = 25

bdc = 185 - 4(25) = 185 - 100 = 85