tolong dijawab ya kaka please dua duanya

no.21
(3x+15)° + (2x-5)° = 90°
3x°+15°+2x°-5° = 90°
5x°+10° = 90°
5x° = 90°-10°
5x° = 80°
x° = 80°÷5
x° = 16°

2x-5= 2(16)-5
= 32-5
= 27° [b]

no. 22
(3x+10)°+(7x+20)° = 180°
3x°+10°+7x°+20° = 180°
10x°+30° =180°
10x° = 180°-30°
10x° = 150°
x° = 150°÷10
x = 15

7x+20= 7(15)+20
=105+20
=125° [d]