Question

Variable y varies directly with x^2, and y = 32 when x = 4.

Which graph represents the quadratic variation?

Answer 1

A. http://static.k12.com/calms_media/media/1540000_1540500/1540310/1/e704306724d0e3058f5f975d02ad64262eb5d886/MS_ALG_S2_01_12_quiz_Q5a_question.gif

Answer 2

B. http://static.k12.com/calms_media/media/1540000_1540500/1540311/1/d3c9c95d917ce7280f5dbce58d52cc1b289e4903/MS_ALG_S2_01_12_quiz_Q5b_question.gif

Answer 3

C. http://static.k12.com/calms_media/media/1540000_1540500/1540312/1/520c64d5cf628a3b4b22b816792234a7675902b7/MS_ALG_S2_01_12_quiz_Q5c_question.gif

Answer 4

D. http://static.k12.com/calms_media/media/1540000_1540500/1540313/1/69f31c1a860fc344187f2804ec831319d4f09b69/MS_ALG_S2_01_12_quiz_Q5d_question.gif

Answer 5

@misty1212

Answer 6

HI!!

Answer 7

Hello!

Answer 8

\[y=kx^2\] we need \(k\)

Answer 9

Would k be 32?

Answer 10

Or no y is 32

Answer 11

no dear
put \(x=4,y=32\) and solve
\[32=k\times 4^2\] for \(k\)

Answer 12

\[32=16k\\k=?\]

Answer 13

Ok soo k=2?

Answer 14

yes, and the equation is
\[y=2x^2\]

Answer 15

@TwiztTiez After misty finishes helping you, compare this to the previous question and look at the pattern, ok? =]

Answer 16

Ok thanks

Answer 17

\[\color\magenta\heartsuit\]

Answer 18

But wait now that i have k would i do 32=2x4^2??

Answer 19

@misty1212

Answer 20

??

Answer 21

Anyone?

Answer 22

@Nnesha

Answer 23

Hello?

Answer 24

@pitamar is that what i do?

Answer 25

Hello!?

Answer 26

Sorry, I'm back. let me see

Answer 27

Ok

Answer 28

The thing is that you got k out of 32 = k*4^2. that's why you know k=2.
The power this gives you is that now you know the equation is:
$$
y = 2 \cdot x^2
$$
And you can find the 'y' values for other points.
Take a point you see in the graphs, (say x=2 as we did in previous question), plug it in the equation and see what the 'y' value has to be.
Now check what graph is matches those (x,y) values.

Answer 29

So A?

Answer 30

Yes

Answer 31

Now look at the previous question and see that it is pretty much the same and that you understand the idea. ok?

Answer 32

Yeah ok

Answer 33

I see now thanks!

Answer 34

Sure np =)