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44 votes
A pair of numbers that have the sum of 14 and a difference of four

User Huangbiubiu
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1 Answer

19 votes
19 votes

Answer: The two numbers are 9 and 5

9+5 = 14

9-5 = 4

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Step-by-step explanation:

Let x and y be the unknown numbers. I'll make x the larger item.

The original instructions translate to these equations

x+y = 14

x-y = 4

Add the equations straight down

  • The x terms add to 2x
  • The y terms add to 0 and go away
  • The right hand sides add to 14+4 = 18

We have the new equation 2x = 18 which solves to x = 9

If x = 9, then y = 5 because we can see that either

x+y = 14

9+y = 14

y = 14-9

y = 5

or,

x-y = 4

9-y = 4

-y = 4-9

-y = -5

y = 5

Therefore, the two numbers are 9 and 5.

A quick check verifies this:

9+5 = 14

9-5 = 4

User Lazywei
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3.1k points