Question

2. Solve 4x=28 by finding square roots.

I don't know what this question wants? If it wants me to solve for x, then obviously x=7. But it's asking for square roots so...?

Answer 1

that's super confusing. are you sure it's not x^2 or something??

Answer 2

No it's definitely 4x=28. I'm not sure what it wants me to do... I've been working on quadratic factoring lately, so maybe it has something to do with that?

Answer 3

hmmm. so quadratic factoring. you could subtract 28 from both sides to get 4x-28=0, factor out 4 to get 4(x-7)=0 but that's still not using square roots, that's just a more roundabout way of doing it

Answer 4

Yeah I have no idea what it has to do with square roots. :/

28 is not a perfect square, and x isn't squared either, so I have no clue.

Answer 5

Can you help me with this one instead @bigsby123 ?

3. Find the x-intercepts of y = −3x2 + 4x + 4 using the Quadratic Formula.

Answer 6

sure. so do you know the quadratic formula?

Answer 7

Maybe you can refresh my memory on it. I'm not sure what it's asking for. What are x-intercepts?

Answer 8

ok, so the quadratic formula is -b +/- sqrt ((b^2-4ac)/2a), where a=the coefficient next to x^2, b =coefficient next to x, and c=the number

Answer 9

and the point of the quadratic formula is to find the x intercepts. the quadratic formula is set equal to x

Answer 10

Oh right. I remember that formula now. So I plug the numbers from #3 into that formula and x is my answer?

Answer 11

correct. so tell me what you get as the x intercepts when you are finished. :)

Answer 12

Hahahahaha I just figured out what was wrong with #2 and #3! The exponent is there, but it's really tiny and transparent. So apparently number 2 is 4x^2=28.

Answer 13

ok, that makes a lot more sense!

Answer 14

I will solve number 3 first and then go back to number 2.

Answer 15

also, I had a typo: the quadratic formula is only square rooted over the numerator of the fraction, not the entire thing. sorry

Answer 16

@bigsby Okay here's what I got so far:
x=-4(+-)8/6

Hopefully that makes sense. I had the correct formula written in my book already so don't worry. How do I simplify from this point?

Answer 17

check your denominator again. remember because it is 2a, and a is -3, you're going to get a negative number

Answer 18

other than that, you're correct!

Answer 19

Good thing you caught that! I had that written down but I forgot to write it on here.

So is this what I would put as my final answer? Or could I simplify further?

Answer 20

I put it as: x=2/3 or x=-2/3

Answer 21

Nevermind it's x=-2/3 or x=2

Answer 22

You are going to end up with two answers in the form of x=__ and ___. So if you choose the + path first, you would go through this process: -4+8/-6=-2/3. However, for the - path, it will be -4- 8/-6=2

Answer 23

nice job!

Answer 24

Thanks! Now I just have to go back to number 2.

2. 4x^2=28

Answer 25

Ok, so do you know where to start?

Answer 26

I think so. You subtract 28 over to the left side to get: 4x^2-28=0

Answer 27

sure, that's one way to do it! so now what do you do?

Answer 28

I'm not sure. Can you help me remember what to do from here? I always have trouble factoring..

Answer 29

I would factor out a 4 to get 4(x^2-7)=0. Do you know what to do next?

Answer 30

No I don't know what to do. :(

Answer 31

ok, divide 4 by both sides. What do you have now?

Answer 32

*on

Answer 33

I don't get when you're supposed to use square roots on this if 28 isn't a perfect square...

Answer 34

@bigsby123 Okay I'll try what you said. You say to divide 4 by both sides? What do you mean by that?

Answer 35

@bigsby123 Hello?

Answer 36

so when you divide by 4 on both sides you're going to get x^2-7=0. Add 7 to both sides to get x^2=7. Then what do you do?

Answer 37

en you divide by 4 on both sides you're going to get x^2-7=0. Add 7 to both sides to get x^2=7. Then what do you do?

Answer 38

Are you solving for x?

Answer 39

yes, so this is when the square root comes in. square root both sides to get x= +/- sqrt 7

Answer 40

got it?

Answer 41

Oh okay, so then the answer is sqrt 7. I thought you were supposed to factor for this question, but apparently not. THanks for the help!

Answer 42

yup!

Answer 43

How do you do this one?

10. Use GCF to factor 15x^2+6x