a) Tính chu vi tam giác ABC biết độ dài 3 cạnh là \(AB = 5\sqrt 2 \left( {cm} \right),AC = \sqrt {32} \left( {cm} \right)\), \(BC = \sqrt {98} \left( {cm} \right)\). (Không yêu cầu vẽ hình)
b) Thu gọn: \(B = \sqrt {{{\left( {\sqrt 7 - 1} \right)}^2}} - \frac{6}{{\sqrt 7 - 1}}\).
A.\(\begin{array}{l}a)\,\,16\sqrt 2 \,\,cm\\b)\,\,B = - 2\end{array}\)
B.\(\begin{array}{l}a)\,\,16\,\,cm\\b)\,\,B = \sqrt 7 + 1\end{array}\)
C.\(\begin{array}{l}a)\,\,18\sqrt 2 \,\,cm\\b)\,\,B = \sqrt 7 - 1\end{array}\)
D.\(\begin{array}{l}a)\,\,18\,\,cm\\b)\,\,B = \frac{1}{{\sqrt 7 - 1}}\end{array}\)
b) Thu gọn: \(B = \sqrt {{{\left( {\sqrt 7 - 1} \right)}^2}} - \frac{6}{{\sqrt 7 - 1}}\).
A.\(\begin{array}{l}a)\,\,16\sqrt 2 \,\,cm\\b)\,\,B = - 2\end{array}\)
B.\(\begin{array}{l}a)\,\,16\,\,cm\\b)\,\,B = \sqrt 7 + 1\end{array}\)
C.\(\begin{array}{l}a)\,\,18\sqrt 2 \,\,cm\\b)\,\,B = \sqrt 7 - 1\end{array}\)
D.\(\begin{array}{l}a)\,\,18\,\,cm\\b)\,\,B = \frac{1}{{\sqrt 7 - 1}}\end{array}\)
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Hóa Học lớp 12
