SOLUTION: please help me solve this problem x/7-x/3=4

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Question 688435: please help me solve this problem x/7-x/3=4
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x%2F7-x%2F3=4 both sides multiply by LCD of 7 and 3 which is 21 to get a rid of fractions

x%2A21%2F7-x%2A21%2F3=4%2A21

x%2Across%2821%293%2Fcross%287%29-x%2Across%2821%297%2Fcross%283%29=84

3x-7x=84

-4x=84

x=84%2F-4

x=-21