Answers

2015-12-10T20:58:14+08:00
(x + 4) + (x - 1) may become x + 4 + x - 1 :)

x + 4 + x - 1 = 57
    2x + 4 - 1 = 57
         2x + 3 = 57
    2x + 3 - 3 = 57 - 3
              2x = 54
         2÷ 2 = 54 ÷ 2
                x = 27
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2015-12-12T17:06:54+08:00
Just add:
x+4+x-1=57
Add like terms
2x+3=57
Subtract both sides by 3
2x=54
Divide both sides by 2
x=27
Hope this helps =)
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