X (x-6)+20x2=7X-2 решите уровнение

Question

X (x-6)+20x2=7X-2
решите уровнение

Answer 1

X(x-6)+20x^2 = 7x - 2
x^2 - 6x + 20x^2 -7x + 2 = 0
21x^2 -13x + 2 = 0
D = (-13)^2 - 4*2*21 = 169 - 168 = 1
√1 = 1
x_1 = (13+1)/42 = 14/42 = 1/3
x_2 = (13-1)/42 = 12/42 = 2/7 

Answer 2

2х-6х+20х-7х=-2-2
9х=-4
х=9:(-4)
х=-2,25