Question

Решите пожалуйста (7х+4)(2х-1)=1

Answer 1

14x^2 - 7x + 8x - 4 - 1 = 0
14x^2 + x - 5 = 0 
D = 1 + 4*14*5 = 281

x1 = (-1 + VD)/28 = (-1 + V281)/28

x2 = (-1 - V281)/28

Answer 2

$(7x+4)*(2x-1)=1 \ 14x^{2} -7x+8x-4=1 \ 14 x^{2} +x-4=1 \ 14x^{2}+x-5=0 \ D= 1^{2}-4*14*(-5)=281 \ x_{1} = frac{-1+ sqrt{281} }{2*14} =frac{-1+ sqrt{281} }{28} \ x_{2} = frac{-1- sqrt{281} }{2*14} =frac{-1- sqrt{281} }{28}$