Answers

2016-01-19T18:57:51+08:00
3n + 4n = 30
4n = 30
n = 30 / 4
n = 7.5
3(7.5) + 1(7.5) = 30
22.5 + 7.5 = 30
30 = 30
if the number is followed by parenthesis it means multiply it
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