SOLUTION: The sum of two numbers is 28 and their difference is 4. What are their number?

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Question 741320: The sum of two numbers is 28 and their difference is 4.
What are their number?

Found 2 solutions by richwmiller, MathLover1:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
x+y=28
x-y=4
add
2x=32
x=16
y=12

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

let numbers be x and y
if the sum of two numbers is 28, we have
x%2By=28....eq.1
and if their difference is 4, we have

x-y=4....eq.2
solve the system by addition:
x%2By=28....eq.1
x-y=4....eq.2
_________________
x%2Bx%2Bcross%28y%29-cross%28y%29=28%2B4
2x=32
x=32%2F2
highlight%28x=16%29
now find y
16%2By=28....eq.1
y=28-16
highlight%28y=12%29
check:
x%2By=28....eq.1
16%2B12=28
28=28

x-y=4....eq.2
16-12=4
4=4