CPM Homework Help : AC Problem 4-101

Kathy is thinking of a number. When she triples her number, adds eighteen, and then subtracts her original number from the sum, she gets four. What is Kathy's original number?

Hint 1:

Start by writing an equation for the word problem.

$\left(3x + 18\right) – x = 4$

Hint 2:

Solve the equation for $x$ .

$2x + 18 = 4$

Step 2:

$2x = −14$

Answer:

Did you show all of your work?
How can you check your answer?

$x = −7$