Răspuns:
Explicație pas cu pas:
a)
x + 4x+5 = 180° => 5x = 175° => x = 175:5 => x = 35°
b)
5x+3x = 180° => 8x = 180° => x = 180:8 => x = 22°30'
c)
x+70+x-10 = 180° => 2x = 120° => x = 60°
d)
5x+4x = 90° => 9x = 90° => x = 10°
e)
3x+15+2x = 90° => 5x = 75° => x = 15°