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Math Problem , help me please :]?
a*a-b*b=72
a+b= 12
find out a-b is without finding out what a and b are
explain please as this would be in my math test tommorow
2 Answers
- Anonymous7 years ago
First find each sum of 12, which would be
1,11. 2,10. 3,9. 4,8. 5,7 and 6,6
Pick one of the sums, I will pick 6 and 6.
In this case, a = 6 and b = 6.
You then square a, square b and take a from b. If the answer is 72, then do the final sum of 6-6, which is 0
tl;dr the answer is 0
- 7 years ago
a*a-b*b= a^2 - b^2
and a^2 - b^2 = (a+b)(a-b)
so putting the given values,we get :
72 = 12*(a-b)
a-b = 6
