The question
Mia wrote x⁷ · x⁻³ = x²¹. Which is correct?
Mia wrote x⁷ · x⁻³ = x²¹. Which is correct?
x⁷ · x⁻³
x⁷ · x⁻³=x^(7 − 3)
x⁷ · x⁻³=x^(7 − 3)
x⁷ · x⁻³=x⁴
x⁷ · x⁻³=x⁴
they wrote:x²¹
- Do not check by reading their line. Somebody else's working is the most persuasive thing on the page, and rereading it is how you end up agreeing with it — do the step yourself first, then compare.
- On your own, and writing the step nobody writes down: x⁷ · x⁻³ becomes x^(7 − 3).
- Tidy that up and it is x⁴.
- Now compare. They wrote x²¹, and the two powers were multiplied instead of added — so the correct answer is x⁴.
How it works.
- 01
Do not check by reading their line. Somebody else's working is the most persuasive thing on the page, and rereading it is how you end up agreeing with it — do the step yourself first, then compare.
- 02
On your own, and writing the step nobody writes down: x⁷ · x⁻³ becomes x^(7 − 3).
- 03
Tidy that up and it is x⁴.
- 04
Now compare. They wrote x²¹, and the two powers were multiplied instead of added — so the correct answer is x⁴.