What is the solution to this system of linear equations?

x + y = 4

x − y = 6

x=5 , y= -1

Step-by-step explanation:

You can see that one of the y's is negative while the other is positive, so you can add them together.

Now, negative 1 + positive 1 = 0, so the y's cancel out leaving only the x's.

Remember you can't add one part without adding the other so x+x = 2x, and 4+6=10. This makes the final equation 2x=10.

You can simplify that into x=5. This gives you the answer for x

Then substitute x=5 into any of the two equations (doesn't matter) I'll use the first one. So if you substitute it you get 5+y=4.

Simplified, y= -1

Therefore, x= 5 and y=-1

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)

answer: true

step-by-step explanation: