Question

решить уравнение (490-х )-250=70

Answer 1

(490-х )-250=70;
490-x=70+250;
490-x=270;
x=490-270;
x=220.

Answer 2

(490 - х ) - 250 = 70
490 - х = 70 + 250
490 - х = 320
х = 490 - 320
х = 170

давай проверим:
(490 - 170) - 250 = 70
320 - 250 = 70
70 = 70