A.\(\overrightarrow u (0;2;1)\)
B.\(\overrightarrow u (0; - 2;1)\)
C.\(\overrightarrow u ( - 2;1;0)\)
D.\(\overrightarrow u (1; - 2;0)\)

A.26
B.32
C.28 
D.45

A.\(3x + 4y + 2 = 0\)
B.\(3x + 4y - 2 = 0\).
C.\(6x + 8y - 11 = 0\).
D.\(6x + 8y + 11 = 0\).

A.\(\dfrac{a}{3}\)
B.\(\dfrac{{2a}}{3}\)
C. \(\dfrac{{a\sqrt 3 }}{3}\)
D.\(\dfrac{{2a\sqrt 3 }}{3}\)

A.\(a = \sqrt 2 \)
B.\(a = \frac{1}{{\sqrt 2 }}\)
C.\(a = \frac{1}{2}\)
D.\(a = \dfrac{1}{2}\)

A.\(\sqrt {20} \)
B.\(\sqrt {20}  + \sqrt {34} \).
C.\(\sqrt {34} \)
D.\(\sqrt {34}  - \sqrt {20} \)

A.\(7\)
B.\(19\)
C.\(21\)
D.\(38\)

A.\(\dfrac{{\pi {a^2}}}{{\sqrt 3 }}\)
B.\(\dfrac{{2\pi {a^2}}}{{\sqrt 3 }}\). 
C.\(4\pi {a^2}\).
D.\(2\sqrt 3 \pi {a^2}\).

A.\(\sqrt 3 \).
B.\(3\)
C.\(5\)
D.\(\sqrt 5 \).

A.\(27\).
B.\(5\).
C.\(20\).
D.\(23\).