CPM Homework Help : CC2 Problem 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.

Hint:

To triple means to multiply by $3$ , so:

$3x+5=26$

More Help:

Thu's number cannot be $10$ because...

$3·10+5=35$

So what can her number be?

Answer:

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