Question

Could you check this for me?

Answer 1

I know its not step 4 or step 5.. Im thinking its step 6 but im not 100% sure

Answer 2

@dan815

Answer 3

@jim_thompson5910

Answer 4

why are you thinking step 6?

Answer 5

Well I tried to work out the formula and i got to step 5 and it matched up with the steps to step 5 in the pictures. And when i tried to do step 6 i got something different. Maybe i messed up in step 4 or 5 but i believe it would be step 7

Answer 6

I believe it would be step 6*

Answer 7

look at step 3, what is done on this step?

Answer 8

If its not step 6 thats alright, Do you think you could just help me work through the problem?

Answer 9

Theyre making the equation equal to -c/a

Answer 10

what operation are they doing to both sides in step 2 to get to step 3?

Answer 11

Dividing

Answer 12

Well wait they change c/a into -c/a why did that happen?

Answer 13

notice how the c/a moves from one side to the other

how did they get it to move

Answer 14

Im not sure?

Answer 15

they subtracted c/a from both sides

Answer 16

c/a is just a number

Answer 17

By making it equal to 0?

Answer 18

Oh okay i see

Answer 19

'a' and 'c' are numbers

so c/a is some number (a is nonzero)

Answer 20

Okay i see

Answer 21

So how would you tell which step had the mistake?

Answer 22

so is step 6 incorrect?

Answer 23

I dont think it would be now would it?

Answer 24

yeah that -c/a is valid since step 3 is valid

Answer 25

So it is incorrect? or is it correct i got confused, sorry..

Answer 26

It would be correct wouldnt it?

Answer 27

yeah step 6 is actually correct

Answer 28

Okay so how would we find out which one is wrong?

Answer 29

what else were you thinking was incorrect?

Answer 30

Step 7

Answer 31

Well since step 6 was right would it be step 7 just by process of elimination?

Answer 32

why is step 7 incorrect?

Answer 33

Well i only say that because since step 6 correct doesnt that mean the steps before it are correct too?

Answer 34

well you could have something like step 2 incorrect, and then have it build up with correct steps (3 through 7)

but that's not the case here. It turns out step 7 is indeed the incorrect one, but your reasoning/logic is flawed unfortunately. There is another reason why step 7 is incorrect. Look at the transition between step 6 and step 7. What is different?

Answer 35

They changed it to b/4a^2?

Answer 36

they have (b/2a)^2 in step 6
but then it changes to (b/4a)^2 in step 7

Answer 37

why does it change to 4a?

Answer 38

Umm im not sure? Its not suppose to be 4a is it? I thought thats why step 7 is incorrect?

Answer 39

it should stay as 2a, yeah

Answer 40

Okay i understand

Answer 41

I have like a little question to ask before you leave

Answer 42

go ahead

Answer 43

When a question asks what are the solutions to the equation f(x) = g(x)? would the solutions be where they intercept eachother or when they intercept the x axis?

Answer 44

f(x) = g(x) is when the two curves cross or intersect each other

f(x) - g(x) = 0 has you looking for the roots

Answer 45

think of h(x) = f(x) - g(x)

solving h(x) = 0 will give you the roots or x-intercepts

Answer 46

the roots of h(x) correspond to the x coordinates of the intersection of f and g

Answer 47

Well these likes are curved and cross eachother so would it be where they cross eachother?

Answer 48

yeah anywhere you have an intersection point between f and g

Answer 49

http://learn.flvs.net/webdav/assessment_images/educator_algebra1_v17/09_10_part_one/09_10_part1_g11_q02.jpg

Answer 50

heres the picture

Answer 51

it doesn't work for me

Answer 52

that's what i see

Answer 53

ok your second pic works

Answer 54

So would it be where they cross eachother?

Answer 55

yes and i spot 3 points in which they do so

Answer 56

But what confuses me is all the answers say "x ="

Answer 57

Like an example would be x = -1.9, 0.8, 4.1

Answer 58

they want the x coordinates of the intersection points

Answer 59

Okay so x = -1.9, 0.8, 4.1

Answer 60

would be the correct answer

Answer 61

example

f(x) = 2x+5
g(x) = 3x^2-7

solve f(x) = g(x), which is the same as saying 2x+5 = 3x^2-7, to get x = -1.69, 2.36 (solutions are approximate)

Answer 62

yeah those x values you listed look good

Answer 63

Okay i see

Answer 64

Thank you very much, Sir.

Answer 65

yw

Answer 66

@jim_thompson5910 Im so sorry to bother you again but this is the last question im confused upon

Answer 67

Do you think you could help me? Or should i open a new question and ask it there?

Answer 68

either way is fine

Answer 69

The product of (a - b)(a - b) is a2 - b2.

Sometimes
Always
Never

Answer 70

So i was completely confused about this so I went to another openstudy question that asked this but there were different answers. One said never because after you work out the answer it would equal (a-b)^2 the someone said it would be never because after you solve it would be a whole number. Then someone said sometimes because you can use some formula to move the a and b around to where it would equal a2 - b2 sometimes?

Answer 71

I think it would be never because when you solve this it would be (a-b)^2 is that correct?

Answer 72

why not try replacing a and b with numbers? see what happens

example: a = 2, b = 7

Answer 73

Because it would be the same term multiplied by the same term. So it would just be to the second power right?

Answer 74

okay so 2-7 would be -5

Answer 75

what is (a-b)*(a-b) equal to when a = 2, b = 7

Answer 76

would it be 2^2 - 7^2

Answer 77

plug it into (a-b)*(a-b)

Answer 78

(2-7)(2-7)

Answer 79

which results to what?

Answer 80

25?

Answer 81

yep, what is a^2 - b^2 equal to when a = 2, b = 7

Answer 82

2^2 - 7^2

Answer 83

compute that

Answer 84

Im sorry i dont know what that means

Answer 85

oh calculate..

Answer 86

-45

Answer 87

so (a-b)*(a-b) = a^2 - b^2 turns into 25 = -45 when you plug in the 'a' and b values and calculate

Answer 88

Since 25 = -45 is false, this makes (a-b)*(a-b) = a^2 - b^2 false for that (a,b) pair

we can see that (a-b)*(a-b) = a^2 - b^2 isn't always true. But can we say "it's never true" ?

Answer 89

Im not sure? Can it ever be true with a different set of numbers?

Answer 90

When i take test I like to think that Never is a very strong work and i dont ever pick never if im uncertain because i feel like theres sometimes a possibility.. SO would the answer be sometimes?

Answer 91

if it's sometimes, then what is one (a,b) pair that could work?

Answer 92

I dont think there is any actually

Answer 93

there are actually infinitely many pairs. Look at small numbers like -1,0,1,2,...

Answer 94

So it would be sometimes?