tolong bangett yaa kaa nomer 1 beserta caranya

7x +5x = 180
12x = 180
x = 180:12 = 15

Garis dan Sudut

<ABD + <CBD = 180° (berpelurus)
7X + 5X = 180
12X = 180
X = 180 : 12
X = 15

<ABD = 7X
<ABD = 7 x 15
<ABD = 105° (B).

*semoga membantu. sukses selalu ^_^