Mary multiplied a number by -3. When she added the result to 6, she got 12. What is her number?

Question

Mary multiplied a number by -3. When she added the result to 6, she got 12. What is her number?

Answer 1

Let's start out with the statement: Mary multiplied a number by -3.

That would be represented by the term:

-3x

Then we look at the next statement: When she added the result to 6, she got 12.

The result is -3x, and when 6 is added to it, we get 12. This can be written as:

-3x + 6 = 12

Now we work at solving the equation for the variable to find her number. To do this, we follow the order of operations.

Parenthesis None

Exponents None

Add/Subtract -3x + 6 - 6 = 12 -6

-3x = 6

Multiply/Divide (-3/-3)x = 6/-3

x = -2

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