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I have a math question.
What would the answer to this problem be: Solve the Equation: the square root of (2x+5) + the square root of (x) = 2
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Where were you?
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sqrt(2x+5) + sqrt(x) = 2
2x+5+x=4
3x+5=4
You get the idea…
That wouldn’t work though, because of FOIL, so it would really be somethign along the lines of
sqrt(2x+5) + sqrt(x) = 2
2x+5+(sqrt(2x+5)*sqrt(x))+(sqrt(2x+5)*sqrt(x))+x=4
but I sorta forget how to do that part and was wondering if there was an easier way…
I don’t know of any easier ways. Basically it goes
sqrt(2x + 5) + sqrt(x) = 2
2x + 5 + 2 * sqrt(2x^2 + 5) + x = 2
3x + 3 + 2 * sqrt(2x^2 + 5) = 0
3x + 3 = -2 * sqrt(2x^2 + 5)
(3x + 3)^2 = (-2 * sqrt(2x^2 + 5)^2
…and so on…
You look like you have a positive number and it really means 2×5. You normally would use +5 when you have a negative number.
I.E. (-2) x (+4)
I would suspect that (2x+5) is 10 and squared would be 100.
Righto. You’re right it wouldn’t work. But you have an idea of what you’re doing. Reduce the power 1/2 by taking logs.
The left side of this formula follows as:
2X+5+(2*sqrt(2x+5)*sqrt(x)+x=4
next, we combine the X coefficients:
3x+5+2*sqrt(2x+5)*sqrt(x)=4
now, we combine the constants:
3X+(5-4)+2*sqrt(2x+5)*sqrt(5)=0
3x+1+2*sqrt(2X+5)*sqrt(x)=0
There is still the difficulty of solving for the terms within sqare root operands!
Well this is what I got;
(2x+5)^1/2 + x^1/2 = 2
1/2.ln(2x+5) + 1/2.ln(x) = ln(2)
1/2.ln(2x^2+5x) = ln(2)
ln(2x^2+5x) = 2.ln(2)
2x^2+5x = exp(4)
Rearrange to give
2x^2+5x-exp(4)=0
And solve using the quadratic formula to give
x = 5/4 +/- sqrt(25-16exp(2))/4
Arkia vaklar is on to something, by separating the square root expressions to one side of the equals sign and the rest of it to the other.
As I was saying…
-(3x+1)/2=sqrt(2x+5)*sqrt(x)
Then square both sides of the equation. Should I go on?
brunorivera200 wrote:
As I was saying…-(3x+1)/2=sqrt(2x+5)*sqrt(x)
Then square both sides of the equation. Should I go on?
Go on then. I’m intrigued.
fractal.scatter wrote:
Well this is what I got;
(2x+5)^1/2 + x^1/2 = 2
1/2.ln(2x+5) + 1/2.ln(x) = ln(2)
1/2.ln(2x^2+5x) = ln(2)
ln(2x^2+5x) = 2.ln(2)
2x^2+5x = exp(4)
Rearrange to give
2x^2+5x-exp(4)=0
And solve using the quadratic formula to givex = 5/4 +/- sqrt(25-16exp(2))/4
DUH!
Central wrote:
fractal.scatter wrote:
Well this is what I got;
(2x+5)^1/2 + x^1/2 = 2
1/2.ln(2x+5) + 1/2.ln(x) = ln(2)
1/2.ln(2x^2+5x) = ln(2)
ln(2x^2+5x) = 2.ln(2)
2x^2+5x = exp(4)
Rearrange to give
2x^2+5x-exp(4)=0
And solve using the quadratic formula to givex = 5/4 +/- sqrt(25-16exp(2))/4
DUH!
I’m not sure how I’m supposed to take that ‘DUH’?
fractal.scatter wrote:
Central wrote:
fractal.scatter wrote:
Well this is what I got;
(2x+5)^1/2 + x^1/2 = 2
1/2.ln(2x+5) + 1/2.ln(x) = ln(2)
1/2.ln(2x^2+5x) = ln(2)
ln(2x^2+5x) = 2.ln(2)
2x^2+5x = exp(4)
Rearrange to give
2x^2+5x-exp(4)=0
And solve using the quadratic formula to givex = 5/4 +/- sqrt(25-16exp(2))/4
DUH!
I’m not sure how I’m supposed to take that ‘DUH’?
DUH as in, “DUH! That was soo easy even a rock could figure it out… thank you captain obvious!” said in a sarcastic tone…
Central wrote:
DUH as in, “DUH! That was soo easy even a rock could figure it out… thank you captain obvious!” said in a sarcastic tone…
Okay.
After reading this post and the replies that went with it, my brain exploded!!!!
Ugh!!!!
X will be equal to -1/3.
First you square both sides to give you 2x + 5 + x = 4
3x = -1
x = -1/3
Yeah mine too T-T
theres like 5 different answers here ….
swirly51 wrote:
X will be equal to -1/3.
First you square both sides to give you 2x + 5 + x = 4
3x = -1
x = -1/3
Er… no.
swirly51 wrote:
X will be equal to -1/3.
First you square both sides to give you 2x + 5 + x = 4
3x = -1
x = -1/3
(a + b)^2 is not the same as a^2 + b^2. Things do not work that way.
my answer is correct. you go square all of both sides then solve for x. haha i had a 96% in advanced functions and 95% in calculus and vectors. i know what im doing.
ohhhhhhhh HAHA wow im an idiot. never mind im totallllllly wrong
swirly51 wrote:
ohhhhhhhh HAHA wow im an idiot. never mind im totallllllly wrong
Yeah I hate iot when that happens lol.
swirly51 wrote:
ohhhhhhhh HAHA wow im an idiot. never mind im totallllllly wrong
Haha, it happens to all of us.
DUH!
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