Question

Help me evaluate this expression please

Answer 1

idk

Answer 2

Thank you for your effort @Catbuck1

Answer 3

I can guide through if you want

Answer 4

That would be superb

Answer 5

First step is to foil the expression

Answer 6

I remember what that stands for, but not how to use it

Answer 7

Basically it goes like this a(b+c) = ab + ac

Answer 8

So \[\sqrt(7)\sqrt(x)+\sqrt(7)-7\sqrt(7)\]

Answer 9

Correct?

Answer 10

It's a \(\sqrt{7x}\) that you have outside parentheses, and the second term should be a multiplication.
\[\sqrt{7x}\sqrt{x}-\sqrt{7x}*7\sqrt7\]

Answer 11

Ah ok

Answer 12

What next?

Answer 13

You regroup the roots like \(\sqrt{a}*\sqrt{b}=\sqrt{ab}\)

Answer 14

\[\sqrt(x)*7\sqrt(7)\]

Answer 15

is that right?

Answer 16

I have no idea what you did there, did you actually study this stuff ?

Answer 17

Srry lol, so a=sqrt(x) and b = sqrt(7x)??

Answer 18

So combined sqrt(8x)???

Answer 19

Ok here's an example \[\sqrt{12}*\sqrt{3}=\sqrt{12*3}=\sqrt{36}=6\]

Answer 20

Alright so \[\sqrt(x)*\sqrt(7x)=\]

Answer 21

Is that the right first part?

Answer 22

Yes so what do you find ?

Answer 23

\[\sqrt(7x*x) = \sqrt(8x)\]

Answer 24

That doesn't have a square so that would be my answer?

Answer 25

Don't add. That's a multiplication sign yo

Answer 26

sqrt(14x)?

Answer 27

Ok what is x*x ?

Answer 28

AHA 7x^2

Answer 29

Thank god !

Answer 30

which makes my answer 7x

Answer 31

Why'd you get the 7 out of the root ?

Answer 32

Omg sorry for being so slow, I'm not usually this bad

Answer 33

Because isn't\[\sqrt(x^2)=x\]

Answer 34

No it totally ok, just take your time and do it step by step

Answer 35

No that's fine but the 7 should stay inside : \[\sqrt{7x^2}=\sqrt{7}*\sqrt{x^2}=\sqrt{7}x\]

Answer 36

And I should give my answer as \[\sqrt(7x)^2\]

Answer 37

right?

Answer 38

or as sqrt(7x)?

Answer 39

It's sqrt(7)*x
And that's just the first part, this is the expression you're simplifying remember ?
\[\sqrt{7x}\sqrt{x}-\sqrt{7x}*7\sqrt7\]So we still need to simplify the second term.

Answer 40

Ah ok so now we've got\[\sqrt(7*x) - \sqrt(7x)*7\sqrt(7)\]

Answer 41

The x is outside the root ;]
\[\sqrt{7}*x-\sqrt{7x}*7\sqrt7\]

Answer 42

Can you do the same for the second term ?

Answer 43

How would the 7*sqrt(7) come into play?

Answer 44

It's the same trick, you just keep the 7 outside the root.

Answer 45

So then\[\sqrt(7x*7) *7\]

Answer 46

sqrt(7^2 * x) *7?

Answer 47

Yep, go on !

Answer 48

Then sqrt(x) *7 *7

Answer 49

or sqrt(x) 7^2 i guess?

Answer 50

Correct !

Answer 51

So then the evaluation is \[\sqrt(7)*x-\sqrt(x) * 7^2\]

Answer 52

Yep !

Answer 53

Wow Tysm you were fantastically helpful

Answer 54

I feel so accomplished now haha