tolong ya jwaban no 5 am cara nya

Diketahui :
< ECB = 5x + 30°
< BOC = 2x + 10°
< ECB + < BOC = 180°

Ditanya :
a. Nilai x = ...?
b. besar < EOB = ...?
c. besar < BOC = ...?

Jawab :
a. 180° = <EOB + <BOC
180° = (5x+30°) + (2x+10°)
180° = 7x + 40°
180° - 40° = 7x
140° = 7x
140°/7 = x
20° = x

b. < EOB = 5x + 30°
= 5 . 20° + 30°
= 100° + 30°
= 130°

c. < BOC = 2x + 10°
= 2 . 20° + 10°
= 40° + 10°
= 50°

Itu soalnya gak sesuai sama gambar.. jd jawabannya di gambar aja ya

Coba cek lagi ya, kalo bener boleh ya dijadiin jawaban terbaik.. thank you :D