A (relatively) Simple Radical Equation: 4p^{1/2} + 5p = 0

gus123671

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Hello.
Could anyone explain how to solve for p in the following equation without factoring out p1/2? That method really confuses me and severely threw me off when I encountered it.

4p1/2+5p = 0
 
Can you solve this? [math]4z + 5z^{2} = 0[/math]
 
Hello.
Could anyone explain how to solve for p in the following equation without factoring out p1/2? That method really confuses me and severely threw me off when I encountered it.

4p1/2+5p = 0
You really should be able to handle \(\displaystyle 1-\frac{1}{2}\) and know that \(\displaystyle \frac{1}{2}<1\)

4p1/2+5p = p1/2(4+ 5p1/2)=0

So either p1/2=0 or (4+ 5p1/2)=0
Continue....
 
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Could anyone explain how to solve for p in the following equation without factoring out p1/2? That method really confuses me and severely threw me off when I encountered it.

4p1/2+5p = 0
Can you solve this? [math]4z + 5z^{2} = 0[/math]

Do you see what tkhunny is hinting at? You can do a substitution, letting [MATH]z = p^{1/2}[/MATH].

Of course, in a sense you will still be factoring out [MATH]p^{1/2}[/MATH], but it will be called [MATH]z[/MATH] while you are doing it!

Another way is to isolate [MATH]p^{1/2}[/MATH], which is [MATH]\sqrt{p}[/MATH], and then square both sides. This is a standard way to solve radical equations. I don't think this is the best way, though.

But it might be a good idea to look at the equation a little first. Notice that [MATH]4p^{1/2}[/MATH] is non-negative. Does that imply anything about p?
 
But it might be a good idea to look at the equation a little first. Notice that [MATH]4p^{1/2}[/MATH] is non-negative. Does that imply anything about p?
Ouch, I did not see that-until I factored. Thanks!
 
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