Question

Answer 1

Xét \(\Delta ABC:\)

\(DE//BC\left(gt\right).\)

\(\Rightarrow\dfrac{AD}{DB}=\dfrac{AE}{EC}\left(Talet\right).\)

\(Thay:\) \(\dfrac{4}{2}=\dfrac{6,5}{x}.\Rightarrow x=\dfrac{13}{4}.\)

Answer 2

ta có: DE // BC

=> \(\dfrac{AD}{BD}=\dfrac{AE}{EC}\)

<=> \(\dfrac{4}{2}=\dfrac{6,5}{x}\)

<=> x= 6,5 . 2 =13