A.Fe + dung dịch HCl.
B.Fe + dung dịch FeCl3.
C.Cu + dung dịch FeCl2.
D.Cu + dung dịch FeCl3.

A.Tinh bột.
B.Fructozơ.
C.Saccarozơ.
D.Glucozơ.

A.38,93 gam.
B.25,95 gam.
C.77,86 gam.
D.103,85 gam.

A.\({i_3} = 2\cos \left( {{\omega _3}t + \frac{\pi }{2}} \right)\,\,\left( A \right)\).
B.\({i_2} = 2\cos \left( {{\omega _2}t - \frac{\pi }{4}} \right)\,\,\left( A \right)\).
C.\({i_4} = \sqrt 2 \cos \left( {{\omega _4}t - \frac{\pi }{6}} \right)\,\,\left( A \right)\).
D.\({i_1} = \sqrt 2 \cos \left( {{\omega _1}t - \frac{\pi }{6}} \right)\,\,\left( A \right)\).

A.625
B.120
C.118
D.237

A.1
B.2
C.3
D.4

A.9
B.7
C.6
D.8

A.501
B.180
C.851
D.150

A.x = 2, y = 1.
B.x = 1, y = 9.
C.x = 9, y = 1.
D.x = 1, y = 2.

A.59
B.29
C.19
D.49