The perimeter of a triangle is 15x2−23x+9 and two of its sides are 5x2+8x−1 and 6x2−9x+4. Find the third side.
The perimeter of triangle =15x2−23x+9
Length of one side =5x2+8x−1
Length of other side =6x2−9x+4
Sum of the lengths of the two sides =(5x2+8x−1)+(6x2−9x+4)=11x2−x+3
∴ Length of the third side = Perimeter of the triangle − Sum of the other two sides
=(15x2−23x+9)−(11x2−x+3)
=15x2−23x+9−11x2+x−3
=4x2−22x+6