M = mass
p = density
v = volume
Yes, to find m it would be m = pv.
To find v that would be m/p.
Answer: at most 15 pairs of socks
Step-by-step explanation:
Let the number of pair of socks of her sister be
, and let the number of pairs Lucy has be
.
Since , Lucy has 4 more than 1/3 the number of pairs of socks as her sister, this means that
.............................. equation 1
Also , Lucy has at most 9 pairs of socks , this means that
....................................... equation 2
Equating the two equations , we have

multiply through by 3

subtract 12 from both sides

Therefore , the sister has at most 15 pairs of socks
Answer:
Usually there are the variables x y z but it doesn't matter what they are.
Step-by-step explanation:
First choose your first variable to solve. Find x by putting all the numbers and variables to one side.
once you found x substitute the answer for x in all the equations. Next find y and substitute your answer in all the equations again.
Once you have solved 2 variables then you are able to solve z.
If you have questions please feel free to ask in the comments below.
The answer to this question is C
ANSWER

EXPLANATION
Since the directrix is

the axis of symmetry of the parabola is parallel to the y-axis.
Again, the focus being,

also means that the parabola will open upwards.
The equation of parabola with such properties is given by,

where

is the vertex of the parabola.
The directrix and the axis of symmetry of the parabola will intersect at

The vertex is the midpoint of the focus and the point of intersection of the axis of the parabola and the directrix.
This implies that,

and

The equation of the parabola now becomes,


Thus, the distance between the vertex and the directrix.
This means that,

Since the parabola opens up, we choose

Our equation now becomes,

This simplifies to

or

This is the same as,

The correct answer is D .