Question 595537
Hi, there--
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We can solve this problem by writing an algebraic equation.
Let's call the mystery number n. Now we need to translate the English sentence into algebra.
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In algebra, "seven times a number" is 7n.
In algebra, "3 times the number" is 3n.
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The sentence says that 7n is 12 more than 3n, so we write
{{{7n=12+3n}}}
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Now we solve the equation for n.
{{{7n=12+3n}}}
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Subtract 3n from both sides.
{{{4n=12}}}
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Divide both sides by 4.
{{{n=3}}}
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According to computations, the number is 3. We need to go back and check our work. Reread the sentence substituting "3" for "a number."
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"Seven times THREE is the same as 12 more than 3 times THREE." We know that 7x3=21 and 3x3=9, so we have "21 is 12 more than 9." This is true, so the number is 3.
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That's it. Feel free to email me if this explanation is confusing.
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Mrs.Figgy
math.in.the.vortex@gmail.com