第8页 - 亮点给力提优课时作业本九年级数学江苏版

A

D

B

$\frac{3}{2}$

$\frac{\sqrt{3}}{2}$

$x_{1}=1，x_{2}=\frac{1}{2}$

＞

A

B

$解：x^2+\frac 12x=1$

$x^2+\frac 12x+\frac {1}{16}=1+\frac {1}{16}$

$(x+\frac {1}{4})^2=\frac {17}{16}$

$x+\frac {1}{4}=±\frac {\sqrt {17}}4$

$x_1= \frac {\sqrt {17}-1}4 ，x_2=\frac {-\sqrt {17}-1}4$

$解：y^2-\frac {\sqrt 2}2y=1$

$y^2-\frac {\sqrt 2}2y+\frac {1}{8}=1+\frac {1}{8}$

$(y-\frac {\sqrt 2}4)^2=\frac {9}{8}$

$y-\frac {\sqrt 2}4=±\frac {3\sqrt 2}4$

$y_{1}=\sqrt 2，y_{2}=-\frac {\sqrt 2}2$

$解：t^2-\frac {2}{3}t=\frac {5}{3}$

$t^2-\frac {2}{3}t+\frac {1}{9}=\frac {5}{3}+\frac {1}{9}$

$(t-\frac {1}{3})^2=\frac {16}{9}$

$t-\frac {1}{3}=±\frac {4}{3}$

$t_{1}=\frac {5}{3}，t_{2}=-1$