Walter and Brian each have a CD collection. • The number of CDs in Walter's collection can be represented by x. • The number of CDs in Brian's collection is 3 times the number in Walter's collection. • The total number of CDs in both collections is 144. What is x, the number of CDs in Walter's collection?

Number of CDs in Walter's collection = x = 36

Step-by-step explanation:

x denotes number of CDs in Walter's collection.

Also, the number of CDs in Brian's collection is 3 times the number in Walter's collection.

Number of CDs in Brian's collection

Total number of CDs in both Walter's collection and Brian's collection = 144

So,

Number of CDs in Walter's collection = x = 36

up

step-by-step explanation:

the orientation of the parabolas can easily be found by analysing the power of x and y and their signs. if x is squared , parabola opens up and also if its coefficient is negative it opens down. if y is squared , the parabola opens right and also if its coefficient is negative it opens left. however in order to do the above analysis our equation must be in standard form .

our parabola is

which is not standard form of any parabola . hence we square on both hand side and convert it into standard form.

hence we see that x is squared and its coefficient is non negative . there for it opens up.