Объяснение:

[tex] \frac{2x {}^{2} + x - 1 }{5x {}^{2} + 6x + 1} = \frac{(2x - 1)(x + 1)}{(x + 1)(5x + 1)} = \frac{2x - 1}{5x + 1} [/tex]

[tex]\dfrac{2x^2+x-1}{5x^2+6x+1}=\dfrac{2(x+1)(x-0.5)}{5(x+1)(x+0.2)}=\dfrac{(x+1)(2x-1)}{(x+1)(5x+1)}=\dfrac{2x-1}{5x+1}\qquad x\ne-1; \ -0.2[/tex]

[tex]2x+x-1=0\\D=1+8=9\\\\x_{1,2}=\dfrac{-1\pm3}4=-1;\ 0.5[/tex]

[tex]5x^2+6x+1=0\\D=36-20=16\\\\x_{1,2}=\dfrac{-6\pm4}{10}=-1;\ -0.2[/tex]