# Tried this equation everywhere

### Tried this equation everywhere

This costed me 2 pts on a quiz
(2x+7)^(2x+7)=3125
Probably getting the answer to this tomorrow but if someone could solve it would be cool.
Thank you.
Barabbas

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Joined: Sun Dec 02, 2018 12:48 pm
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Guest

### Re: Tried this equation everywhere

If x=-1 ,then

$$(2(-1)+7)^{(2(-1)+7)}$$=

=$$5^{5}$$=(5.5)(5.5)5=

=25.25.5=625.5=

=3 125

So -1 is root.
Guest

### Re: Tried this equation everywhere

Barabbas wrote:This costed me 2 pts on a quiz
(2x+7)^(2x+7)=3125
Probably getting the answer to this tomorrow but if someone could solve it would be cool.
Thank you.

The first thing I would do is let y= 2x+ 7 so the equation becomes y^y= 3125. Then I would think about factoring 3125. Obviously 25 is a factor: 3125= 25(125). And 125= 5(25) so 3125= (25)(25)(5)= 5^5. Aha! y^y= 5^5 so y= 2x+ 7= 5. 2x= 5- 7= -2 and x= -1.
Guest

### Re: Tried this equation everywhere

Seeing that "3125" the first thing I would do is factor it. $$3125= 5^5$$. So I want 2x+ 7= 5.
Guest