The area of the region enclosed by the parabolas y = x2 - 5x and y = 7x - x2 is .
Answer
72
Solution
Intersection: x2 - 5x = 7x - x2 2x2 - 12x = 0 x = 0, 6
[figure]
on (0, 6) the curve y = 7x - x2 is above y = x2 - 5x
Area = 06 [(7x - x2) - (x2 - 5x) ]dx = 06 (12x - 2x2) dx
= [6x2 - 2x33 ]06 = 216 - 144 = 72 sq. units
Answer: 72
Note: The official NTA answer key gives 198. Our faculty team has re-checked this question and finds 72 correct, as explained above.