Question 943678: Anne solved 5(2x)- 3 = 20x + 15 for x by first distributing 5 on the left side of the equation. She got the answer x = -3. However, when she substituted -3 into the original situation for x, she saw that her answer was wrong. What did Anne do wrong, and what is the correct way?
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617)   (Show Source):
Answer by MathTherapy(10552)  (Show Source):
You can put this solution on YOUR website! Anne solved 5(2x)- 3 = 20x + 15 for x by first distributing 5 on the left side of the equation. She got the answer x = -3. However, when she substituted -3 into the original situation for x, she saw that her answer was wrong. What did Anne do wrong, and what is the correct way?
She seemed to have distributed the 5 on the entire left side of the equation instead of only distributing
the 5 to the 2x. This is what she might've done:
5(2x - 3) = 20x + 15
10x - 15 = 20x + 15
10x - 20x = 15 + 15
- 10x = 30
 , or 
Correct solution, since she was wrong, as well as the person who responded:
5(2x) - 3 = 20x + 15
10x - 3 = 20x + 15
10x - 20x = 15 + 3
- 10x = 18
 , or  , or 
You can do the check!!
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