-5х^2+15х+2х-6=0
-5х^2+17х-6=0 |*-1|
5х^2-17х+6=0
Д=17^2-4*5*6=289-120=169=13^2
x1=17+13\5*2=30\10=3 x2=17-13\10=5\10=0,5
Меньший их корней: х2=0,5
1) (3x - x^2)/2 - (2x^2 - x)/6 = x
3(3x - x^2) - (2x^2 - x) = 6x
9x - 3x^2 - 2x^2 + x - 6x = 0
-5x^2 + 4x = 0
x1 = 0; x2 = 4/5
2) x^2 / (2-x) - 3x / (2-x) = 0
(x^2 - 3x) / (2 - x) = 0
x ≠ 2
x1 = 0; x2 = 3
3) (x^2 - 2x) / (x+4) - (x-4) / (x+4) = 0
(x^2 - 2x - x + 4) / (x + 4) = 0
x ≠ - 4
x^2 - 3x + 4 = 0
D = 9 - 4*4 = 9 - 16 = - 7 < 0
Решений нет
4) (5x-7) / (x-3) - (4x-3) / x = 0
[(5x-7)*x - (4x-3)(x-3)] / [x(x-3)] = 0
x ≠ 0; x ≠ 3
5x^2 - 7x - 4x^2 + 15x - 9 = 0
x^2 + 8x - 9 = (x-1)(x+9) = 0
x1 = - 9; x2 = 1