Question

The sum of two numbers is 12. The difference of the same two numbers is −4. Find the two numbers.

Answer 1

Answer:

  4 and 8

Step-by-step explanation:

Let 'a' represent one of the numbers. Then the other is 12-a, and their difference is ...

  a - (12-a) = -4

  2a = 8 . . . . add 12

  a = 4 . . . . . divide by 2

  12-a = 8 . . . . find the other number

The two numbers are 4 and 8.

Answer 2

Answer: x = 4, y = 8

Step-by-step explanation:

Let the two numbers be x and y

sum of the two numbers will be

x + y =  12 ------------------------------1

Difference of the two numbers

x - y  =  -4 ----------------------------- 2

Now, to find the two numbers , we solve equation 1 & 2 together

  x + y =  12

  x - y  =  -4

we now add the two equations to eliminate y

   2x =  8

      x = 4.  Now to find the value of y, we substitute for x in any of the equation above

 x + y  = 12

 4  + y = 12

        y =  12 - 4

        y  =  8