A symbol, usually a letter, that represents an unknown quantity is called a .

What is the value of the digit 1 in the number 13?

Segment xz is bisected by point y. if xy = 12x, and the measure of xz = 18x – 6, solve for x

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?