a) 10x - 9x + 10 = 13
x + 10 = 13
x = 13 - 10
x = 3
б) 11y + 18y - 46 = 70
29y - 46 = 70
29y = 70 + 46
29y = 116
y = 116 : 29
y = 4
Ответ: a) x = 3; б) y = 4