Question

What is the simplified form of each expression?

7x^–8 × 6x^3

a. 42/x^5
b. 1/42x^5
c. 42x^11
d. 13x^–5

(–2x8) · 3y9 · 2x4

a. 3x^12y^9
b. –12x^72y^9
c. –12xy^21
d. –12x^y^9

Find the simplified form of the expression. Give your answer in scientific notation.

(8 x 10^7) (7 x 10^4)

a. 1.5 × 10^12
b. 5.6 × 10^12
c. 1.5 x 10^29
d. 5.6 x 10^29


(7 × 10^–4)(9 × 10^–10)

a. 6.3 × 10^–13
b. 63 × 10^–13
c. 6.3 × 10^–15
d. 6.3 × 10^–16

Answer 1

it is not good to post multiple questions

Answer 2

Can you do the first one?

Answer 3

first one --- a.

Answer 4

first, the numbers can be multiplied . 6*7=42
so you can rule out some of the choices that way

Answer 5

Thanks GiGlgo3

Answer 6

b.
http://www.mathway.com/math_image.aspx?p=-12xSMB02ESMB0312SMB02eSMB03ySMB02ESMB039SMB02eSMB03?p=76?p=22

Answer 7

second, there is the idea that anything divided by itself is 1
so if you see x/x
\[ \frac{x}{x} =1 \]
or
\[ \frac{x\cdot x}{x\cdot x } =1 \]

2nd, remember that x^3 (for example) means x*x*x (x times itself 3 times)

I would rewrite the x's by flipping the negative one to get
\[ \frac{x^3}{x^8} \]
if we expand it we get
\[ \frac{x*x*x}{x*x*x*x*x*x*x*x} \]
now for every x on the top and bottom we can divide (because x/x=1)
\[ \cancel{\frac{x*x*x}{x*x*x}}\frac{1}{x*x*x*x*x} \]
so the x's are (using the short hand
\[ \frac{1}{x^5} \]
of course we still have the 6*7=42 so the answer is
\[ \frac{42}{x^5} \]

Answer 8

Wow! Thank you!

Answer 9

That is how it works, but people pretty quickly figure out that if they combine the exponents -8+3 = -5 you get the answer right away

Answer 10

so the answer could be written 42 x^(-5) or 42/x^5

Answer 11

Can you help me with the 3rd and 4th one?

Answer 12

me?

Answer 13

Yes!

Answer 14

3. ---- b.

Answer 15

Can you explain?

Answer 16

yes

Answer 17

Sorry if its trouble...I just like to know how you got it:) It helps me understand:)

Answer 18

im here, im using notepad. (:

Answer 19

Okay:)

Answer 20

Can you do that last question...and explain?

Answer 21

You there?

Answer 22

first step

10 to the seventh power is 10000000 times 8 is 80000000

10 to the fourth power is 10000 times 7 is 70000

80000000 times 70000 is 5600000000000

Answer 23

Wow your good

Answer 24

step 2:

10 to the 12th power is 1000000000000 (hint 12 zeros)

1000000000000 times 1.5 is 500000000000... thats not right now is it?

Answer 25

step 3:

10 to the 12th power is 1000000000000 (hint 12 zeros)

1000000000000 times 5.6 is 5600000000000.. that's right!

so b. is the right answer... (:

Answer 26

can you try and do five, or do you need a walkthrough again??

Answer 27

So the last problems first step would be 630000000000000000?

Answer 28

let me think

Answer 29

The zeros get me confused! lol

Answer 30

yea, you are riight

Answer 31

Yay!

Answer 32

Okay...I need help on the last steps though

Answer 33

im here

Answer 34

Can you help me with the last steps?

Answer 35

So its 6.3 x 10^-13?

Answer 36

yes

Answer 37

I cant believe i got that!

Answer 38

(:

Answer 39

Thank you:)

Answer 40

bye, i have to go, remember, just message me. (:

Answer 41

okay?

Answer 42

Oh I meant thank you before you said message me. Okay byeee!