Here are some worked examples to help get a feel for basic operations in this introduction to algebra.
Problem 1. Find the sum of 4x, 3x, −2x, −x
4x + 3x + −2x + −x = 4x + 3x − 2x − x (Note that + ×− = −)
Problem 2. Find the sum of 5x, 3y, z, −3x, −4y and 6z
5x + 3y + z + −3x + −4y + 6z = 5x + 3y + z − 3x − 4y + 6z = 5x − 3x + 3y − 4y + z + 6z = 2x − y + 7z
Note that the order can be changed when terms are separated by + and − signs. Only similar terms can be combined.