12. If a + b = 5 and a2 + b2 = 13, find ab.
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Answered by
3
Answer:
(a+b)^2=5^2
a2 + a2 + 2ab=25
13+2ab=25
2ab=25-13=12
Therefore ab=12/2=6
Answered by
1
Given
a + b = 5
a^2 + b^2 = 13
(a + b)^2 = a^2 + b^2 + 2*ab
5^2 = 13 + 2*ab
2*ab = 5^2 - 13
2*ab = 25 - 13
2*ab = 12
ab = 6 ——> Answer
a + b = 5
a^2 + b^2 = 13
(a + b)^2 = a^2 + b^2 + 2*ab
5^2 = 13 + 2*ab
2*ab = 5^2 - 13
2*ab = 25 - 13
2*ab = 12
ab = 6 ——> Answer
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