A.\(F = 0\)
B.\(F = 1\)
C.\(F = -1\)
D.\(F = 2021\)

A.\(S = \left\{ {\dfrac{5}{2};\dfrac{5}{4}} \right\}.\)
B.\(S = \left\{ {\dfrac{5}{2};\dfrac{5}{3}} \right\}.\)
C.\(S = \left\{ {\dfrac{5}{3};1} \right\}.\)
D.\(S = \left\{ {\dfrac{5}{3};\dfrac{5}{4}} \right\}.\)

A.\(\left( {x;y} \right) = \left\{ {\left( {\dfrac{{ - 5 - \sqrt {13} }}{3};\dfrac{{ - 17 - \sqrt {13} }}{3}} \right),\left( {\dfrac{{ - 5 + \sqrt {13} }}{3};\dfrac{{ - 17 + \sqrt {13} }}{3}} \right)} \right\}\)
B.\(\left( {x;y} \right) = \left\{ {\left( {\dfrac{{ - 5 - 2\sqrt {13} }}{3};\dfrac{{ - 17 - 2\sqrt {13} }}{3}} \right),\left( {\dfrac{{ - 5 + 2\sqrt {13} }}{3};\dfrac{{ - 17 + 2\sqrt {13} }}{3}} \right)} \right\}\)
C.\(\left( {x;y} \right) = \left\{ {\left( {\dfrac{{ - 5 - 2\sqrt {13} }}{3};\dfrac{{ - 15 - 2\sqrt {13} }}{3}} \right),\left( {\dfrac{{ - 5 + 2\sqrt {13} }}{3};\dfrac{{ - 15 + 2\sqrt {13} }}{3}} \right)} \right\}\)
D.\(\left( {x;y} \right) = \left\{ {\left( {\dfrac{{ - 5 - \sqrt {13} }}{3};\dfrac{{ - 15 - \sqrt {13} }}{3}} \right),\left( {\dfrac{{ - 5 + \sqrt {13} }}{3};\dfrac{{ - 15 + \sqrt {13} }}{3}} \right)} \right\}\)

A.\(\left( { - 1;0} \right);\left( {0; \pm 1} \right);\left( {1; \pm 2} \right);\left( {3;t} \right)\,\,\left( {t \in \mathbb{Z}} \right)\,\)
B.\(\left( {1;0} \right);\left( {0; \pm 1} \right);\left( { - 1; \pm 2} \right);\left( {2;t} \right)\,\,\left( {t \in \mathbb{Z}} \right)\,\)
C.\(\left( { - 1;0} \right);\left( {0; \pm 1} \right);\left( {1; \pm 2} \right);\left( {2;t} \right)\,\,\left( {t \in \mathbb{Z}} \right)\,\)
D.\(\left( {1;0} \right);\left( {0; \pm 1} \right);\left( { - 1; \pm 2} \right);\left( {3;t} \right)\,\,\left( {t \in \mathbb{Z}} \right)\,\)

A.\(N\left( {3;4} \right)\)
B.\(M\left( {4;3} \right)\)
C.\(P\left( { - 3;4} \right)\)
D.\(Q\left( {4; - 3} \right)\)

A.Lào Cai.
B.Phú Yên.
C.Hải Phòng.
D.Quảng Ninh.

A.Au.
B.Ag.
C.Al.
D.Cu.

A.Be.
B.K.
C.Ba.
D.Na.

A.Na2CO3.
B.Ca(OH)2.
C.Na3PO4.
D.H2SO4.

A.Al.
B.Fe.
C.K.
D.Ag.