Correct Answer - Option 2 : 4x
2 - 22x + 6
Given
The perimeter of a triangle is (15x2- 23x + 9)
Two of its sides are (5x2 + 8x -1) and (6x2 - 9x + 4)
Concept
Perimeter of a triangle = Sum of the lengths of its three sides.
Calculation
⇒ 15x2- 23x + 9 = (5x2 + 8x -1) + (6x2 - 9x + 4) + third side
⇒ 15x2- 23x + 9 = (11x2 - x + 3) + third side
⇒ The third side = (15x2- 23x + 9) - (11x2 - x + 3)
⇒ The third side = 4x2 - 22x + 6
∴ The third side = 4x2 - 22x + 6