Tính $\widehat {BKE} + \widehat {BCE}$.

$(x - 2)(x + 2)(x + 1)$

$(x - 4)(x + 4)(x + 1)$

$(x - 2)(x + 2)(x - 1)$

$({x^2} + 4)(x + 1)$

$236400$ đồng

$239400$ đồng

$240400$ đồng

$239600$ đồng

$24$ quyển 

$20$ quyển

$4$ quyển 

$22$ quyển

$24$ quyển 

$20$ quyển

$4$ quyển 

$22$ quyển

$\Delta BEK \backsim \Delta CEA$

$\Delta BEK \backsim \Delta CBE$

$\Delta BEK \backsim \Delta CEB$

$\Delta BEK \backsim \Delta ECB$

$BE = 2\sqrt 2 \,cm;\dfrac{{BE}}{{EK}} = 2;\dfrac{{CE}}{{EB}} = 2$

$BE = 2\sqrt 2 \,cm;\dfrac{{BE}}{{EK}} = 2\sqrt 2 ;\dfrac{{CE}}{{EB}} = \dfrac{{\sqrt 2 }}{2}$

$BE = 2\sqrt 2 \,cm;\dfrac{{BE}}{{EK}} = \sqrt 2 ;\dfrac{{CE}}{{EB}} = \sqrt 2$      

$BE = \sqrt 2 \,cm;\dfrac{{BE}}{{EK}} = \sqrt 2 ;\dfrac{{CE}}{{EB}} = \sqrt 2$