$9. 15×\sqrt{14}-6×\sqrt{14}$
$=(\_\_\_\_\_\_-\_\_\_\_\_\_)×\sqrt{14}$
$=9\sqrt{14}$
$19×\sqrt{17}×4×\sqrt{17}$
=(\_\_\_\_\_\_×\_\_\_\_\_\_)×(\_\_\_\_\_\_×\_\_\_\_\_\_)
=76×17
=(\_\_\_\_\_\_)

19×√17×4×√17
=(19×4)×(√17×√17)
=76×17
=1292

10. $(-11)+(+16)+(-\dfrac{2}{5})$
$=+(\quad\quad-\quad\quad)+(-\dfrac{2}{5})$
$=(+5)+(-\dfrac{2}{5})$
$=+(\quad\quad-\quad\quad)$
$=+(\quad\quad)$
$(-5)×(+\dfrac{4}{5})+(-5)×(-\dfrac{4}{5})$
$=-(5×\dfrac{4}{5})+[◯(5×\dfrac{4}{5})]$
$=(-4)+(\quad\quad)$
$=(\quad\quad)$

$(-11)+(+16)+(-\dfrac{2}{5})$
$=+(16 - 11)+(-\dfrac{2}{5})$
$=(+5)+(-\dfrac{2}{5})$
$=+(5 - \dfrac{2}{5})$
$=+(\dfrac{23}{5})$
$(-5)×(+\dfrac{4}{5})+(-5)×(-\dfrac{4}{5})$
$=-(5×\dfrac{4}{5})+[+(5×\dfrac{4}{5})]$
$=(-4)+(4)$
$=(0)$

11. 计算下列各式。
$(+7.3)+(+3.7)$
$(-42)+(-16)+(+18)$
$0+(-39.9)$
$(+\dfrac{2}{5})+(-\dfrac{1}{6})+(+\dfrac{2}{5})+(+\dfrac{1}{6})$

11 $-40$ $-39.9$ $\dfrac{4}{5}$