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Question
If a + b = 7 and ab = 12, find the value of a2 + b2
Solution
We have to find the value of `a^2 +b^2`
Given `a + b = 7 ,ab = 12`
Using identity `(a+b)^2 = a^2 + 2ab +b^2`
By substituting the value of a + b = 7 ,ab = 12we get
`(a+b)^2 = a^2 +b^2 + 2 xx ab`
`(7)^2 = a^2 +b^2 + 2 xx 12`
`49 = a^2 +b^2 + 24`
By transposing +24 to left hand side we get ,
`49 - 24 = a^2 +b^2`
`25 = a^2 +b^2`
Hence the value of `a^2 +b^2 ` is 25.
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