superman10 superman10
  • 01-04-2016
  • Mathematics
contestada

the sum of two numbers is 30 & their difference is 12.

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apologiabiology
apologiabiology apologiabiology
  • 01-04-2016
x+y=30
x-y=12
add them together

x+y=30
x-y=12+
2x+0y=42

2x=42
divide 2
x=21

subsitute
x+y=30
21+y=30
subtrat 21
y=9


number sare 21 and 9
Answer Link
graceh2426
graceh2426 graceh2426
  • 01-04-2016
The answer is 21 and 9. You can use guess and check to solve this. If you add 21 and 9, the sum is 30, and if you subtract 9 from 21, the difference is 12. 
Answer Link

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