1)5х кв+4х-1=0 ,2)16х кв-2Х-5= 0

1) [latex]5 x^{2} +4x-1=0 \\ D=16-4*5*(-1)=16+20=36 \\ \sqrt{D} = \sqrt{36} =6[/latex] [latex] x_{1}= \frac{-4+6}{2*5} =0.2 \\ x_{2} = \frac{-4-6}{2*5} =-1[/latex] Ответ:-1;0,2 2)[latex]16 x^{2} -2x-5=0 \\ D=4-4*16*(-5)=4+320=324 \\ \sqrt{D}= \sqrt{324} =18[/latex] [latex] x_{1} = \frac{2+18}{2*16}= \frac{20}{32}= \frac{5}{8} =0.625[/latex] [latex] x_{2}= \frac{2-18}{2*16}=- \frac{16}{32} = -\frac{1}{2} =-0.5 [/latex] Ответ: -0,5;0,625