( x - 3 )² + ( x + 4 )² - ( x - 5 )² = 17x + 24
x² - 6x + 9 + x² + 8x + 16 - ( x² - 10x + 25 ) = 17x + 24
2x² + 2x + 25 - x² + 10x - 25 = 17x + 24
x² + 12x - 17x - 24 = 0
x² - 5x - 24 = 0
D = 25 + 96 = 121 = 11²
x1 = ( 5 + 11 ) : 2 = 8
x2 = ( 5 - 11 ) : 2 = - 3