when x=4, y=25.
a) find an expression for y in terms of x.
b) calculate y when x=2
c) calculate x when y=9
2007-02-25 05:38:55 · 5 answers · asked by jenny 1 in Science & Mathematics ➔ Mathematics
by the way i dont know if this helps but the first part of the question states that y is directly proportional to the square of x
2007-02-25 05:52:02 · update #1
If y is directly proportional to x squared then the generic equation you need is
y = k x^2
Substituting the figures given makes k = 25/16
For the other two parts substitute for the known variable i.e.
b) y = 25 2^2 / 16
= 25/4 or 6.25
c) 9 = 25 x^2 /16
x = root (16 * 9 / 25)
= 4 * 3 / 5
= 12 / 5 or 2.4
2007-02-25 20:43:33 · answer #1 · answered by tringyokel 6 · 0⤊ 0⤋
If when x=4 y=25, then solve for x. which will be x=(25/4)y. To solve for y, you get (4/25)x=y. This will help you solve for your b) and c).
2007-02-25 05:47:17 · answer #2 · answered by Anonymous · 0⤊ 0⤋
a.y=kx
25=4k
k=25/4
b.y=(25/4)x
when x=2 y=25/2
c.9=(25/4)x
x=9(4/25)=36/25
2007-02-25 05:46:20 · answer #3 · answered by raj 7 · 0⤊ 0⤋
Directly proportional means that y = kx, for some number k.
In this case, you can find k by using the information given (it is 6.25).
Now you can apply this to b) and c).
2007-02-25 05:46:34 · answer #4 · answered by r7stuart 3 · 0⤊ 0⤋
No. that's a ingredient of the equation for tension of a fluid (gasoline or liquid) on a floor. tension = tension * area ===> you could exchange tension, area, or the two. they're self reliant of one yet another
2016-12-18 10:43:34 · answer #5 · answered by ? 3 · 0⤊ 0⤋