Найдите корень уравнения:
а) (x + 2) + x = 9;
б) x + (7 + x) = 11;
в) x + 2x − 5 = 40;
г) x + (4 + x) + x = 16.
(x + 2) + x = 9
x + 2 + x = 9
2x = 9 − 2
2x = 7
x = 7 : 2
x = 3,5
x + (7 + x) = 11
x + 7 + x = 11
2x = 11 − 7
2x = 4
x = 4 : 2
x = 2
x + 2x − 5 = 40
3x = 40 + 5
3x = 45
x = 45 : 3
x = 15
x + (4 + x) + x = 16
x + 4 + x + x = 16
3x = 16 − 4
3x = 12
x = 12 : 3
x = 4
