Chắc đề là rút gọn \(\sqrt{9-2\sqrt{14}}\)
\(=\sqrt{7-2\sqrt{7}.\sqrt{2}+\sqrt{2}}=\sqrt{\left(\sqrt{7}-\sqrt{2}\right)^2}=\sqrt{7}-\sqrt{2}\)
Bài 2: Căn thức bậc hai và hằng đẳng thức căn bậc hai của bình phương
Các câu hỏi tương tự
\(\left(\sqrt{2}-\sqrt{7}\right)-5\sqrt{9+2\sqrt{14}}\)
Rút gọn
\(\sqrt{9-2\sqrt{14}}\)
d) \(\sqrt{x^2-12x+36}-x=3\)
e) \(\sqrt{x^2-4x+5}-1=x\)
f) \(\sqrt{x^2-6x+9}+x=3\)
h) \(\sqrt{18x}+\sqrt{32x}-14=0\)
k) \(\sqrt{6x-3}+2=\sqrt{3}\)
Tính
A sqrt{4+sqrt{15}}- sqrt{4-sqrt{15}} -sqrt{2-sqrt{3}}
B sqrt{9-2sqrt{14}} +sqrt{9-2sqrt{14}}
C left(4+sqrt{15}right) left(sqrt{10}-sqrt{6}right) sqrt{4-sqrt{15}}
D dfrac{2+sqrt{3}}{sqrt{2}+sqrt{2}+sqrt{3}} + dfrac{2-sqrt{3}}{sqrt{2}-sqrt{2sqrt{3}}}
Đọc tiếp
Tính
A= \(\sqrt{4+\sqrt{15}}\)- \(\sqrt{4-\sqrt{15}}\) -\(\sqrt{2-\sqrt{3}}\)
B= \(\sqrt{9-2\sqrt{14}}\) +\(\sqrt{9-2\sqrt{14}}\)
C= \(\left(4+\sqrt{15}\right)\) \(\left(\sqrt{10}-\sqrt{6}\right)\) \(\sqrt{4-\sqrt{15}}\)
D= \(\dfrac{2+\sqrt{3}}{\sqrt{2}+\sqrt{2}+\sqrt{3}}\) + \(\dfrac{2-\sqrt{3}}{\sqrt{2}-\sqrt{2\sqrt{3}}}\)
Tínha.sqrt{8+2sqrt{5}} b.sqrt{10-2sqrt[]{5}} c.sqrt{5+sqrt{24}} d.sqrt{12-sqrt{140}} e.sqrt{14+2sqrt{5}} f. sqrt{8-sqrt{28}} g.sqrt{23-4sqrt{15}} h.sqrt{9+4sqrt{2}} giúp mik vs mai mik nộp rồi,cảm ơn mn nhiều
Đọc tiếp
Tính
a.\(\sqrt{8+2\sqrt{5}}\) b.\(\sqrt{10-2\sqrt[]{5}}\) c.\(\sqrt{5+\sqrt{24}}\) d.\(\sqrt{12-\sqrt{140}}\)
e.\(\sqrt{14+2\sqrt{5}}\) f. \(\sqrt{8-\sqrt{28}}\) g.\(\sqrt{23-4\sqrt{15}}\) h.\(\sqrt{9+4\sqrt{2}}\)
giúp mik vs mai mik nộp rồi,cảm ơn mn nhiều
B1:tính :
a)\(\sqrt{4+2\cdot\sqrt{3}}-\sqrt{13-4\cdot\sqrt{3}}\)
b)\(\sqrt{14+4\cdot\sqrt{3}}-\sqrt{9-4\cdot\sqrt{2}}\)
B2; cmr :
a)\(\sqrt{x^2+2x+5}\ge2\)
b)\(\sqrt{x^2-4}+\sqrt{x-2}=0\)
1.sqrt{frac{129}{16}+sqrt{2}}
2.sqrt{frac{289+4sqrt{72}}{16}}
3. sqrt{2-sqrt{3}}.left(sqrt{6}+sqrt{2}right)
4.left(sqrt{21}+7right).sqrt{10-2sqrt{21}}
5.2.left(sqrt{10}-sqrt{2}right).sqrt{4+sqrt{6-2sqrt{5}}}
6.left(4sqrt{2}+sqrt{30}right).left(sqrt{5}-sqrt{3}right).sqrt{4-sqrt{15}}
7.left(7+sqrt{14}right).sqrt{9-2sqrt{14}}
Đọc tiếp
1.\(\sqrt{\frac{129}{16}+\sqrt{2}}\)
2.\(\sqrt{\frac{289+4\sqrt{72}}{16}}\)
3. \(\sqrt{2-\sqrt{3}}.\left(\sqrt{6}+\sqrt{2}\right)\)
4.\(\left(\sqrt{21}+7\right).\sqrt{10-2\sqrt{21}}\)
5.\(2.\left(\sqrt{10}-\sqrt{2}\right).\sqrt{4+\sqrt{6-2\sqrt{5}}}\)
6.\(\left(4\sqrt{2}+\sqrt{30}\right).\left(\sqrt{5}-\sqrt{3}\right).\sqrt{4-\sqrt{15}}\)
7.\(\left(7+\sqrt{14}\right).\sqrt{9-2\sqrt{14}}\)
³√(20 + 14√2) + ³√(20 - 14√2) = A. Tính A
chứng minh rằng : (14√14+√12+√30√2+√5).√5−√21=4