an expression is shown below. which value of x makes the expression equivalent to 10 times the square root of 51?

2 times the square root of 51x

Question

an expression is shown below. which value of x makes the expression equivalent to 10 times the square root of 51?

2 times the square root of 51x

parthkohli · Answer

$$2\sqrt{51x} = 10\sqrt{51}$$Any ideas?

anonymous · Answer

a) 5     b)  25   c) 50   d)100

parthkohli · Answer

$$10\sqrt{51} = 2\times 5\sqrt{51}$$And it's given that $2\sqrt{51x} = 2\times 5\sqrt{51}$. 

Begin with cancelling $2$ and $\sqrt{51}$ from both sides. You are left with $\sqrt{x} = 5$

parthkohli · Answer

Do you get what I said?

anonymous · Answer

Yes I do. thank you so much(:

parthkohli · Answer

So what do you get for the answer?

anonymous · Answer

a...right?

parthkohli · Answer

How do you get that?

anonymous · Answer

..uh yeah im lost Cx im not good with algebra. could you explain?

parthkohli · Answer

Can you first show what you tried at least?

anonymous · Answer

I mean like, I don't know it. I don't know what to do at all. I just thought 5 was the answer..but I have no idea how to show the work

parthkohli · Answer

Did you understand what I did there...?

anonymous · Answer

no

parthkohli · Answer

You earlier said you did. Erm

parthkohli · Answer

Keep reading it. You'll certainly have that "ah!" moment if you try to.

anonymous · Answer

I have no clue what to do. Could you POSSIBLY explain it to me?

parthkohli · Answer

OK. Do you see how $10\sqrt{51} = 2\times 5 \sqrt{51}$?

anonymous · Answer

Yes. That parts simple

parthkohli · Answer

And you want to solve the equation $10\sqrt{51} = 2\sqrt{51x}$ right?

anonymous · Answer

Yes.

parthkohli · Answer

So technically you are solving $2 \times 5\sqrt{51} = 2\sqrt{51x}$. Got it?

anonymous · Answer

yeah. but why does 51 stay the same?

parthkohli · Answer

Why wouldn't it?

anonymous · Answer

I thought that since 51 is multiplied by x that it would change. but clearly it doesn't. i really do not know.

parthkohli · Answer

Umm, we're gonna proceed with stuff. But do you understand it till $2\times 5\sqrt{51}=2\sqrt{51x}$?

anonymous · Answer

I don't understand why x cancels out. So no.

parthkohli · Answer

we haven't done any cancellations till now.

anonymous · Answer

In the first part of the equation you just put, where is the x? I don't understand how it's equal to the second part.

parthkohli · Answer

Err... let's do that again.

The question wants such a value of $x$ in $2\sqrt{51x}$ such that it equals $10\sqrt{51}$. What would you do here?

anonymous · Answer

Okay. Nevermind. I don't get it.. ill find help somewhere else.

parthkohli · Answer

If you want help, why not get it here?