от Xixibg » 16 Дек 2011, 13:23
1.(3x-1)(x+1)(2-x)[tex]\le[/tex] 0 (-1)
[tex]3(x-\frac{1}{3})(x+1)(x-2)\ge 0[/tex]
[tex]=> x\in [-1;\frac{1}{3}]\cup[2;\infty )[/tex]
2.[4-1/4+(1/23/2)-4/3]:(4+2-2)
[tex][2^{-\frac{2}{4}}+(\frac{1}{2}^{\frac{3}{2}})^{-\frac{4}{3}}]:[4+\frac{1}{4}][/tex]
[tex][2^{-\frac{1}{2}}+(\frac{1}{2})^{-2}]:\frac{17}{4}[/tex]
[tex](\frac{\sqrt{2}}{2}+4).\frac{4}{17}[/tex]
[tex]\frac{2\sqrt{2}+16}{17}[/tex]
3.(x2-4x+3):(x-3)[tex]\ge[/tex] 0[tex]DM: x-3\ne0 ; =>x\ne 3[/tex]
[tex]\frac{\cancel{(x-3)}(x-1)}{\cancel{(x-3)}}\ge 0[/tex]
[tex]=>x-1\ge 0 ; => x\ge 1[/tex]
[tex]x\in [1;3)\cup(3;\infty )[/tex]