Evaluating Variable Expressions with Integers
Evaluating Variable Expressions with Integers
Now we’ll practice evaluating expressions that involve subtracting negative numbers as well as positive numbers.
Example
Evaluate \(x-4\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}\)
- \(\phantom{\rule{0.2em}{0ex}}x=3\phantom{\rule{0.2em}{0ex}}\)
- \(\phantom{\rule{0.2em}{0ex}}x=-6.\)
Solution
To evaluate \(x-4\) when \(x=3\), substitute \(3\) for \(x\) in the expression.
| Subtract. |
To evaluate \(x-4\) when \(x=-6,\) substitute \(-6\) for \(x\) in the expression.
| Subtract. |
Example
Evaluate \(20-z\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}\)
- \(\phantom{\rule{0.2em}{0ex}}z=12\phantom{\rule{0.2em}{0ex}}\)
- \(\phantom{\rule{0.2em}{0ex}}z=-12\)
Solution
To evaluate \(20-z\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}z=12,\) substitute \(12\) for \(z\) in the expression.
| Subtract. |
To evaluate \(20-z\phantom{\rule{0.2em}{0ex}}\text{when}\phantom{\rule{0.2em}{0ex}}z=-12,\phantom{\rule{0.2em}{0ex}}\text{substitute}\phantom{\rule{0.2em}{0ex}}-12\phantom{\rule{0.2em}{0ex}}\text{for}\phantom{\rule{0.2em}{0ex}}z\phantom{\rule{0.2em}{0ex}}\text{in the expression.}\)
| Subtract. |
Optional Video: Subtracting Integers
This lesson is part of:
Introducing Integers