Question

The difference of two numbers is 8, and the sum of the squares of these two numbers are 320. what are the numbers​

Answer 1

Answer:

There are two sets of numbers that meet the criteria:

1)  8 and 16, or

2) -8 and -16

Step-by-step explanation:

Let's call the two numbers A and B.

We are told:

1) A-B=8, and

2) A^2 + B^2 = 320

Rearrange 1) to solve for A:

A=8+B

Use this value of A in the second equation:

A^2 + B^2 = 320

(8+B)^2 + B^2 = 320

(64+ 16B + B^2) + B^2 = 320

2B^2 + 16B + 64 = 320

B^2 + 8B + 32 = 160

B^2 + 8B + 32 = 160

B^2 + 8B - 128 = 0

(B+16)(B-8)=0

B is either -16 or +8

Assuming B = 8

Then from A-B=8 we find that A = B+8 and A = 16

Does A^2 + B^2 = 320?

  (16)^2 + (8)^2 = 320?

  256 + 64 = 320?  YES

--------------------------------

Assuming B=-16

If B=-16, then from A-B=8 we find that A = 8+(-16) and A = -8

Does A-B=8?

 -8 - (-16) = 8?  YES

Does A^2 + B^2 = 320?

 (-8)^2 + (-16)^2 = 320?

 64  + 256 = 320?  YES