Question

qual valor da equação 30-20+2x=10

Answer 1

30-20+2x=10
2x=10-30+20
2x=0
x=0/2
x=0

Answer 2

30 - 20 + 2x = 10
2x = 10 - 30 + 20        como os numeros trocaram de lado eles mudam o sinal
2x = 30 - 30
2x = 0
x =   0/2
x =   0 
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ou 
30 - 20 + 2x = 10
30 - 20 - 10 = -2x
-2x = 30 - 20 -10
-2x = 30 - 30
-2x = 0
-x   = 0/-2
 x= 0