# Question Video: Addition and Subtraction of Algebraic Expressions Mathematics • 7th Grade

Add 38π₯ β 33π¦ + 28π§, 24π¦ β 23π₯ β 23π§, and 24π₯ β 11π§ β 17π¦, then subtract the result from 26π₯ β 17π¦ + 19π§.

03:18

### Video Transcript

Add 38π₯ minus 33π¦ plus 28π§, 24π¦ minus 23π₯ minus 23π§, and 24π₯ minus 11π§ minus 17π¦ then subtract the result from 26π₯ minus 17π¦ plus 19π§.

Our first step is to add the three expressions. In order to do this, weβll group or collect the like terms. Weβll group the π₯s, then weβll group the π¦s, then weβll group the π§s.

Grouping the π₯ terms gives us 38π₯ minus 23π₯ plus 24π₯. This is equal to 39π₯. Next, weβll group the π¦ terms: negative 33π¦ plus 24π¦ minus 17π¦. This is equal to negative 26π¦ as negative 33 plus 24 minus 17 is equal to negative 26. Finally, we need to group the π§ terms: 28π§ minus 23π§ minus 11π§. This is equal to minus six π§ as 28 minus 23 minus 11 is equal to negative six.

Adding the three expressions 38π₯ minus 33π¦ plus 28π§, 24π¦ minus 23π₯ minus 23π§, and 24π₯ minus 11π§ minus 17π¦ gives us 39π₯ minus 26π¦ minus six π§. We were then asked to subtract the result from 26π₯ minus 17π¦ plus 19π§. This can be written as 26π₯ minus 17π¦ plus 19π§ minus 39π₯ minus 26π¦ minus six π§.

Once again, we need to group the like terms. 26π₯ minus 39π₯ is negative 13π₯ as 26 minus 39 is negative 13. Negative 17π¦ minus negative 26π¦ is plus nine π¦ as negative 17 minus negative 26 is the same as negative 17 plus 26, which gives us an answer of nine. Finally, 19π§ minus negative six π§ is equal to 25π§ as 19 minus negative six is equal to 25.

This means that our final answer is negative 13π₯ plus nine π¦ plus 25π§.