### Home > AC > Chapter 4 > Lesson 4.2.4 > Problem4-101

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?

Start by writing an equation for the word problem.

$\left(3x + 18\right) – x = 4$

Solve the equation for $x$.

$2x + 18 = 4$

$2x = −14$

Did you show all of your work?
$x = −7$