Question

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.

Answer 1

Answer:

4x² − 22x + 6

Step-by-step explanation:

Perimeter  of a triangle = Side 1 + Side 2 + Side 3

Therefore,

15x² − 23x + 9 = (5x² + 8x − 1 ) + ( 6x² − 9x + 4) + Side 3

15x² − 23x + 9 = 5x² + 8x − 1  +  6x² − 9x + 4 + Side 3

15x² − 23x + 9 = 11x² - x + 3 + Side 3

Find Side 3:

Side 3  = (15x² − 23x + 9) - (11x² - x + 3 )

Side 3  = 15x² − 23x + 9 - 11x² + x - 3

Side 3  = 4x² − 22x + 6

Answer: 4x² − 22x + 6

Answer 2

Perimeter= sum of three sides

15x²-23x+9 = (5x²+8x-1) + (6x² - 9x + 4)+3rd side

15x²-23x+9 = 11x²- x +3 + 3rd side

3rd side = 15x² - 23x + 9 - (11x² - x + 3)

3rd side = 15x² - 23x + 9 -11x² + x - 3

3rd side = 4x² - 22x + 6