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GED Math: Expression and Equations Drill 3, Problem 4. What are the roots of the quadratic equation?
SAT Math 8.5 Algebra and Functions 214 Views
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Description:
SAT Math 8.5 Algebra and Functions
Transcript
- 00:02
Buckle up! It's question time.
- 00:05
When you square a certain number, the result is equal to ten times the number plus the number again.
- 00:11
What is the number?
- 00:14
Another equation given to us in words that we have to translate to numbers…
- 00:18
Let’s call the number we’re looking for x.
Full Transcript
- 00:21
Squaring x gives us x squared… …which equals ten times the number…
- 00:25
10x…plus the number again…so PLUS x.
- 00:30
We can write this as the equation x squared equals 11x.
- 00:34
What number squared equals 11 times that number?
- 00:39
We can solve the problem with a little logic. Well…it must be 11…
- 00:42
See how it works. 11 times 11 is 121. 11 squared is 121 and they equal each other.
- 00:49
If we weren’t sure though, x squared is the same as x times x…
- 00:53
…so we can simply divide x from both sides. The correct answer is 11 and we're done!
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