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Point A lies on the line `y=2x` and the sum of its abscissa and ordinate is 12. Point `B` lies on the x-axis and the line `AB` is perpendicular to the line `y=2x`. Let `O` be the origin. The area of the Delta AOB isA. 20B. 40C. 60D. 80 |
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Answer» Correct Answer - D Let `A(x_(1),y_(1))` `x_(1)+y_(1)=12` `y_(1)=12-x_(1)` A lies on `y=2x` `y_(1)=2x_(1)` `12-x_(1)=2x_(1)` `x_(1)=4` Hence, `A=(4,8)` equation of AB is `x+2y+lamda=0` Eq. (i) passes through (4,8) `becauselamda=-20` `x+2y=20impliesB` is `(20,0)` Area of `DeltaAOB=(20.8)/(2)=80` sq unit |
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