Worked examples
Two examples
Example 1
Find the value of 2a − 3b when a = −1 and b = 4.
- Put the numbers in, with parentheses around the negatives: 2 × (−1) − 3 × 4.
- −2 − 12.
Answer: −14
Example 2
Find the value of a2 + ab when a = −2 and b = 5.
- (−2)2 + (−2) × 5 = 4 + (−10).
Answer: −6
Where this is taught: Algebra Practice 1, “4. Two variables”
The drill
Ten problems
This drill also has challenge problems. They use the same skill, set up the way the GED test sometimes sets up a problem, so that it looks new at first.
How many:
Type each answer, then press Check my answers at the bottom. Commas in large numbers are fine.Write each answer on the line. The answer key, with the reasoning, is on the last page.