Question

If x+y=10 and x-y=6 what is this value of x cube - y cube​

Answer 1

Answer:

x cubed minus y cubed is equal to 504

Step-by-step explanation:

First we need to know what the values of x and y are.  We can do this pretty easily, by just solving both equations for x, and equating them to each other:

With the first:

x + y = 10

x = 10 - y

And with the other

x - y = 6

x = 6 + y

Now that we have two definitions of x, we can say that the expressions are equal, and solve for y:

10 - y = 6 + y

10 - 6 = y + y

4 = 2y

y = 2

And now that we know what y is, we can find x:

x = 10 - y

x = 10 - 2

x = 8

So x is equal to eight.  We can check our answer by plugging x into the other equation and seeing if we get the same value for y:

x - y = 6

8 - y = 6

-y = 6 - 8

-y = -2

y = 2

So we know we solved that correctly.

Now if we cube each number, eight cubed is equal to 512, and 2 cubed is equal to 8.  If we subtract the latter from the former we get 504.

so x cubed minus y cubed is equal to 504