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Playlist Exponents and Radicals 11 videos
We don't like knocking people down to size, but we do like simplifying radicals. Join us?
To solve radical equations, you square both sides, FOIL it out if necessary, and simplify. Ta da!
Start within the parentheses, and then work your way out. Do that, and this expression is yours.
Solving Radical Equations 2159 Views
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Description:
To solve radical equations, you square both sides, FOIL it out if necessary, and simplify. Ta da!
Transcript
- 00:03
Solving radical equations, a la Shmoop. [Disco ball]
- 00:06
Your favorite underground electronica artist DJ UrchinX is spinning beats at a
- 00:11
secret location. He's left two clues both in the form of a radical expression. [DJ playing on a stage]
- 00:15
Solve them and you'll be one of the first people on earth to hear his new
- 00:20
music. Here's the first clue, square root of 3 X minus 2 equals square root of x [Equation written on a post-it note]
Full Transcript
- 00:26
plus 6 solve for X. First sqaure both sides to get rid of the square roots
- 00:31
leaving us with 3 x minus 2 equals x plus 6. Next add 2 to both sides and subtract [Chainsaw chopping through a log]
- 00:39
X from both sides, we get 2x equals 8 divide both sides by 2 and boom x equals 4.
- 00:47
The next one's a little more complicated, square root of 3x plus 4 equals x minus 5. [Next problem written on a post-it note]
- 00:54
Square both sides to get rid of the square root on the left side and we get
- 00:59
3x plus 4 equals X minus 5 in parentheses squared. Now we're gonna
- 01:05
use foil on the right side, we can start by multiplying X by X which gives us x [Tin foil wrapped into a ball]
- 01:10
squared then we multiply X by minus 5 and we get -5x. We continue by
- 01:17
multiplying minus 5 by X we get minus 5x and we finish by multiplying minus 5 by
- 01:23
minus 5 which equals positive 25, our new equation now reads 3x plus 4 equals x
- 01:31
squared minus 10x plus 25. Subtract 3x and 4 from both sides and we
- 01:39
get x squared minus 13x plus 21 equals 0. Using the quadratic formula to solve for
- 01:48
X is shown as x equals negative b plus or minus the square root of b squared [Man looks excited and says 'Look a cheatsheet!']
- 01:54
minus 4ac (breathes in) all over 2a. We see that X equal 13 plus or minus the square root
- 02:02
of negative 13 squared minus 4 times 21 times 1 over 2. This simplifies into x
- 02:10
equals 13 plus or minus the square root of 169 minus 84 over 2. Therefore the
- 02:18
answer is x equals 13 plus or minus the square root of 85 over 2. Now it can't be
- 02:25
reduced any further just like your friends interest in going to this gig. [Woman looks happy that the problem is solved]
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