Hình 1:

Xét Δ ABC có:

$\widehat{A}$+$\widehat{B}$+$\widehat{C}$`=180^0`

`x+80^0 +50^0=180^0`

`x=180^0-50^0-80^0`

`x=50^0`

Hình 2:

Ta có:

$\widehat{FDE}$ `=35^0+35^0=70^0`

Xét Δ DFE có:

$\widehat{FDE}$ + $\widehat{E}$ + $\widehat{F}$ `=180^0`

`70^0 + 30^0 + y=180^0`

`y=180^0-30^0-70^0`

`y=80^0`

Xét Δ DFG có:

$\widehat{FDG}$ + $\widehat{F}$ + $\widehat{G}$ `=180^0`

`35^0 + 80^0 + y=180^0`

`z=180^0-80^0-35^0`

`z=65^0`

Đáp án:x=50,z=65,y=80

Hinh 1:Ta co:Tong 3 goc trong tam giac =180

vay A+B+C=180 hay A+80+50=180 suy ra A=180-80-50=50

vay x=50

Hinh 2:Trong tam DGE co G+D+E=180 suy ra G=180-30-35=115

ma ta thay goc DGE+GGD=180(hai goc ke bu)

suy ra DGE=180-115=65(z=65)

Trong tam giac DFG co D+G+F=180 hay 35+65+F=180

suy ra F=180-35-65=80(y=80)

vay z=65;y=80