Производная функции, заданной параметрически:
14x² - 5x - 1 = 0
D = 25 + 56 = 81 ; √ D = 9
x1 = ( 5 + 9 ) : 28 = 14/28 = 0,5
x2 = ( 5 - 9 ) : 28 = - 4/28 = - 1/7
( x + 3 ) / 7 = ( 2x - 1 ) / 5
5( x + 3 ) = 7( 2x - 1 )
5x + 15 = 14x - 7
14x - 5x = 15 + 7
9x = 22
x = 2 4/9