SOLUTION: The sum of two number is 30 and the difference of their square is 180.find the number

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Question 935314: The sum of two number is 30 and the difference of their square is 180.find the number

Answer by MathLover1(20849) About Me  (Show Source):
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The sum of two number is 30
x%2By=30....eq.1
and the difference of their square is 180
x%5E2-y%5E2=180....eq.2
find the numbers:
x%2By=30....eq.1...solve for x
x=30-y...substitute in eq.2
%2830-y%29%5E2-y%5E2=180....eq.2...solve for y

900-60y%2Bcross%28y%5E2%29-cross%28y%5E2%29=180
900-60y=180
900-180=60y
720=60y
720%2F60=y
highlight%28y=12%29
now find x
x=30-y
x=30-12
highlight%28x=18%29