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Solve fo x : 3x²-22x23=0

 Apr 1, 2017

Best Answer 

 #3
avatar+118703 
+4

Hi Sara :)

 

Lets see :)

 

3x222x23=0 =(22)24323=(8+24)=32Positive so this means it has 2 real roots 

x=b±b24ac2ax=b±2ax=22±3223x=22±4223 x=22±4223×33x=26±466x=6±263x=6(1±2)3x=363orx=63x=6orx=63

 

I checked this answer by graphing it and it is correct.

 

 Apr 1, 2017
 #1
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+1

Solve for x: P.S. This is how I read it: sqrt(3x^2) - 2sqrt(2x) - 2sqrt(3) = 0, solve for x
-2 sqrt(3) - 2 sqrt(2) sqrt(x) + sqrt(3) sqrt(x^2) = 0

Add 2 sqrt(3) to both sides:
sqrt(3) x - 2 sqrt(2) sqrt(x) = 2 sqrt(3)

Subtract sqrt(3) x from both sides:
-2 sqrt(2) sqrt(x) = 2 sqrt(3) - sqrt(3) x

Raise both sides to the power of two:
8 x = (2 sqrt(3) - sqrt(3) x)^2

Expand out terms of the right hand side:
8 x = 3 x^2 - 12 x + 12

Subtract 3 x^2 - 12 x + 12 from both sides:
-3 x^2 + 20 x - 12 = 0

The left hand side factors into a product with three terms:
-(x - 6) (3 x - 2) = 0

Multiply both sides by -1:
(x - 6) (3 x - 2) = 0

Split into two equations:
x - 6 = 0 or 3 x - 2 = 0

Add 6 to both sides:
x = 6 or 3 x - 2 = 0

Add 2 to both sides:
x = 6 or 3 x = 2

Divide both sides by 3:
x = 6 or x = 2/3

-2 sqrt(3) - 2 sqrt(2) sqrt(x) + sqrt(3) sqrt(x^2) ⇒ -2 sqrt(3) - 2 sqrt(2) sqrt(2/3) + sqrt(3) sqrt((2/3)^2) = -8/sqrt(3) ≈ -4.6188:
So this solution is incorrect

-2 sqrt(3) - 2 sqrt(2) sqrt(x) + sqrt(3) sqrt(x^2) ⇒ -2 sqrt(3) - 2 sqrt(2) sqrt(6) + sqrt(3) sqrt(6^2) = 0:
So this solution is correct

The solution is:
Answer: | x = 6

 Apr 1, 2017
 #2
avatar+302 
+1

could u explain using latex? i did'nt get it

SARAHann  Apr 1, 2017
 #3
avatar+118703 
+4
Best Answer

Hi Sara :)

 

Lets see :)

 

3x222x23=0 =(22)24323=(8+24)=32Positive so this means it has 2 real roots 

x=b±b24ac2ax=b±2ax=22±3223x=22±4223 x=22±4223×33x=26±466x=6±263x=6(1±2)3x=363orx=63x=6orx=63

 

I checked this answer by graphing it and it is correct.

 

Melody Apr 1, 2017
 #4
avatar+302 
0

Thx Mel!

SARAHann  Apr 3, 2017

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