Question

2.

(3 pt)
Which is the quadratic variation equation for the relationship?

y varies directly with x2 and y = 72 when x = 6.


A.
y = x2 + 25

B.
y = 2x2

C.
y = 4x2

D.
y = 12x

Answer 1

Direct variation is y = k x^2 where k is some constant

Plug in y = 72 and x = 6 into the above and solve for k

Then the requred equation is y = k x^2 (insert the found value of k)

Answer 2

thx for helping me

Answer 3

A. - Constant Term - BAD
y = x2 + 25

B.
y = 2x2

C.
y = 4x2

D. - No Squared Term - BAD
y = 12x

Looks like it's down to B or C.

Answer 4

1. Any equation that does not have an exponential value for X is a linear one. Therefore only option D is non linear 2. Y is 3 times the value of X; Therefore Y=3X
3. A number times 3 squared =36; A number times3x3=36, A number=36/9, A number = 4. Therefore Y=4X squared.
4> Inverse: As one increases, the other value decreases. Option A with X values of 2345 and Corresponding Y value of Y 30, 20, 15, 12,. We ask a question what value can we divide 2 into to obtain Y value of 30 : What value/2=30; what value =2 x 30; what value =60. Therefore f(X0 =60/X; We test, X value of 3; 60/3=20; X value of 4; 60/4=15; X value of 5; 60/5=12 We vsee only option A will fit this pattern.
5. When X =2, Y will equal 5 ; Therefore we can say : What value /X=5; Replacing X with 2, we can say what value/2=5; Multiplying both side by 2 we have 2x what value,2=2x5 ; 2/2=1 so we can say 1 Times what value =10, We can say The value =10 ; Therefore we can say: 10(what value)/2(X)=5 and 10/X=Y or Y=10/X
I've gone about this in a slow methodically way to show the reasoning to help you remember. Hope this helps. Good Luck