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Home > CC2 > Chapter 1 > Lesson 1.1.3 > Problem 1-18

1-18.

Thu wants to play “Guess My Number.” She states, “When I triple my number and add five, I get twenty-six. What is my number?” What is her number? Show how you know. Homework Help ✎

To triple means to multiply by 3, so:

3 x + 5 = 26

Thu's number cannot be 10 because...

3 · 10 + 5 = 35

So what can her number be?

Her number is 7. Be sure to show why this is the answer.