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Noah is solving the inequality 7x+5>2x+35 first he solves the equation 7x+5=2x+35 and gets x=6

Noah is solving the inequality 7x+5>2x+35 first he solves the equation 7x+5=2x-example-1
User Meisterluk
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1 Answer

14 votes
14 votes

Here are the steps in solving the equation

7x+5 = 2x+35

7x-2x = 35-5

5x = 30

x = 30/5

x = 6

And here are the steps to solving the inequality

7x+5 > 2x+35

7x-2x > 35-5

5x > 30

x > 30/5

x > 6

The two batches of steps are nearly identical. All I've done is replaced the equal sign with the > sign. The inequality sign stays the same the entire time since we didn't multiply or divide both sides by a negative number.

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In short, Noah's solution of x = 6 is changed to x > 6.

Though this trick only works if we don't multiply or divide both sides by a negative number.

User Robert May
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