1.

`agtb` के लिए यदि `a+b=5` और `ab=6` है तो `(a^(2)-b^(2))` का मान ज्ञात करें?A. 1B. 3C. 5D. 7

Answer» Correct Answer - C
`agtb`
`a+b=5`
`axxb=6` Assume `a=3`
`a^(2)-b^(2)` Values `b=2`
`=9-4=5`
Alternate:
`a+b=5` given
`implies(a+b)^(2)=(5)^(2)`
`a^(2)+b^(2)+2ab=25`
`ab=6` given
`=a^(2)+b^(2)+2xx6=25`
`=a^(2)+b^(2)=13`
`implies a^(2)+b^(2)+2ab-2ab=13`
`a^(2)+b^(2)-2ab=13-2ab`
`(a-b)^(2)=13-2xx6`
`a-b-1`
`:. (a+b)(a-b)`
`a^(2)-b^(2)=5`


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