Worked examples
Two examples
Example 1
Find the value of 3x2 − 2x + 1 when x = 4.
- Put 4 in place of each x: 3 × 42 − 2 × 4 + 1.
- Powers first: 3 × 16 − 8 + 1 = 48 − 8 + 1.
Answer: 41
Example 2
Find the value of x2 + 5x when x = −3.
- Put (−3) in place of each x: (−3)2 + 5 × (−3).
- 9 + (−15) = −6. The square of a negative is positive.
Answer: −6
Where this is taught: Algebra Practice 1, “12. Replace the variable, then follow the order of operations”
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.