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Topmadworld
Hey there,

Answer:
1st no. : x
2nd no. : x + 9 
x + x +9 = 21
x + x = 21 - 9
2x = 12
x = 12 / 2
   = 6
1st number = 6
2nd number = 6 + 9
                    = 15

Hope this helps :D

~Top♥

The two numbers that sum up to 21 and the difference is 9 are 6 and 15.

Let

x = firsts number

y  =second number

Therefore,

Sum of the two numbers

  • x + y = 21

Difference of the two numbers

  • x - y = 9

Therefore,

x + y = 21

x - y = 9

2y = 12

y = 12 / 2

y = 6

x = 21 - 6

x = 15

learn more on algebra here: https://brainly.com/question/1722892?referrer=searchResults