Question

решите уравнение а 15x-8x=21 б 2x+4x=30

Answer 1

15х-8х=21         2х+4х=30
7х=21                6х=30
х=21:7               х=30:6
х=3                    х=5   

Answer 2

15х - 8х = 21
7х = 21
  х = 21 : 7
  х = 3
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2х + 4х = 30
6х = 30
  х = 30 : 6
  х = 5