Question #ade54

1 Answer
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Jun 1, 2017

Answer: #13# and #8#

Explanation:

The sum of 2 numbers is 21 and their difference is 5. Can you find the numbers?

We can write a system of equations, let #x# and #y# be the two numbers. Since it is given that difference between #x# and #y# is not zero, we can assume that one must be greater than the other, say #x>y#:
#x+y=21#
#x-y=5#

Now, we solve the system by elimination. We can add the equations together to eliminate the #y# variable and solve for #x#:
#x+y+x-y=21+5#
#2x=26#
#x=13#

Now, we can substitute back into either of the equations to find #y#, we will use #x-y=5#:
#13-y=5#

Adding #y# to both sides and subtracting #5# from both sides, we get:
#y=8#

Therefore, the two numbers are #13# and #8#

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