Question

The perimeter of a triangle is 15x^2-23x+9 and two of its sides are 5x^2+8x-1 and 6x^2-9x+4.Find third side.

Answer 1

hey here is your answer....

perimeter of a triangle is equal to sum of given sides
let third be "a" then
$(5 {x}^{2} + 8x - 1) + (6 {x}^{2} - 9x + 4) + a = 15 {x}^{2} - 23x + 9 \\ (11 {x}^{2} - x + 3) + a = 15 {x}^{2} - 23x + 9 \\ a = 4 {x}^{2} - 22x + 6$
hope it helps

Answer 2

Perimeter - ( 1st side + 2nd side ) = 3rd side.

15x²-23x+9-(5x²+8x-1+6x²-9x+4)
15x²-23x+9-(11x²-x+3)
15x²-23x+9-11x²+x-3
4x²-22x+6

3rd side will be
4x²-22x+6