x_1=\frac{-b-\sqrt\Delta}{2a} , \qquad x_2=\frac{-b+\sqrt\Delta}{2a}
e)
\sqrt{\frac{1}{4}} + x + x^2 = 4
\frac{1}{2}+x+x^2-\frac{8}{2}=0 \ |*2
2x^2+2x-7=0
a=2, b=2, c=-7
\Delta=b^2-4ac=2^2-4 \cdot 2 \cdot (-7)=60
\sqrt\Delta=\sqrt{60}=\sqrt{4 \cdot 15}=2\sqrt{15}
x_1=\frac{-2-2\sqrt{15}}{2\cdot 2}=\frac{\not2^1(-1-\sqrt{15)}}{\not4^2}=\frac{-1-\sqrt{15}}{2}
x_2=\frac{-2+2\sqrt{15}}{4}=\frac{\not2^1(\sqrt{15})-1}{\not4^2}=\frac{\sqrt{15}-1}{2}
f).
\sqrt9 x^2 - 12x + 4 = 6
3x^2-12x-2=0
a=3, b=-12, c=-2
\Delta=b^2-4ac=144-4 \cdot 3 \cdot (-2)=216
\sqrt\Delta=\sqrt{36 \cdot 6}=6\sqrt6
x_1=\frac{12-6\sqrt6}{2\cdot 3}=\frac{6(2-\sqrt6)}{6}=2-\sqrt6
x_2=\frac{-b-\sqrt\Delta}{2a}=\frac{12+6\sqrt6}{2\cdot 3}=\frac{6(2+\sqrt6)}{6}=2+\sqrt6