a) \(\sqrt[3]{27a^3}\) - 2a
= 3a - 2a = a
b) \(\sqrt[3]{27a^3}\) - \(\sqrt[3]{-8a^3}\)- \(\sqrt[3]{125a^3}\)
= 3a + 2a - 5a = 0
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Bài 9: Căn bậc ba
Các câu hỏi tương tự
A =\(\dfrac{x\sqrt[]{x}-3}{x-2\sqrt[]{x}-3}-\dfrac{2\left(\sqrt[]{x}-3\right)}{\sqrt[]{x}+1}+\dfrac{\sqrt[]{x}+3}{3-\sqrt[]{x}}\)
a. rút gọn A
b. Tính A với x = \(14-6\sqrt[]{5}\)
c. tìm min A
A=\(\dfrac{x\sqrt{x}-3}{x-2\sqrt{x}-3}-\dfrac{2\left(\sqrt{x}-3\right)}{\sqrt{x}+1}+\dfrac{\sqrt{x}+3}{3-\sqrt{x}}\)
a) Rút gọn A
b) Tính A với x=14-6\(\sqrt{5}\)
c) Tìm Min A
1.Chứng minh:\(\dfrac{a+\sqrt{2+\sqrt{5}.}\sqrt{\sqrt{9-4\sqrt{5}}}}{3\sqrt{2-\sqrt{5}}.\sqrt[3]{\sqrt{9+4\sqrt{5}-}3\sqrt{a^2}+\sqrt[3]{a}}}\)=\(-\sqrt[3]{a}-1\)
2.Rút gọn: \(\left(\dfrac{a^3\sqrt[]{a}-2a^3\sqrt{b}+\sqrt[3]{a^2}-\sqrt[3]{b}}{\sqrt[3]{a^2-\sqrt[3]{ab}}}+\dfrac{\sqrt[3]{a^2b}-\sqrt[3]{ab^2}}{\sqrt[3]{a}-\sqrt[3]{b}}\right)1\dfrac{1}{\sqrt[3]{a^2}}\)
Tính:
a)\(\sqrt[3]{125}.\sqrt[3]{\dfrac{16}{10}}.\sqrt[3]{-0,5}\)
b) \(\dfrac{\sqrt[3]{4}+\sqrt[3]{2}+2}{\sqrt[3]{4}+\sqrt[3]{2}+1}\)
c) \(\sqrt{3}+\sqrt[3]{10+6\sqrt{3}}\)
d) \(\dfrac{4+2\sqrt{3}}{\sqrt[3]{10+6\sqrt{3}}}\)
e) E=\(\sqrt[3]{2+10\sqrt{\dfrac{1}{27}}}+\sqrt[3]{2-10\sqrt{\dfrac{1}{27}}}\)
\(\left\{{}\begin{matrix}\sqrt[3]{a+\dfrac{a+1}{3}\sqrt{\dfrac{8a-1}{3}}}+\sqrt[3]{a-\dfrac{a+1}{3}\sqrt{\dfrac{8a-1}{3}}}\\cmvoia>\dfrac{1}{8}thixnguyen\end{matrix}\right.\)
Cho a, b, c, x, y, z thoả mãn: x + y + z = 1 và \(\dfrac{a}{x^3}=\dfrac{b}{y^3}=\dfrac{c}{z^3}\). Chứng minh rằng: \(\sqrt[3]{\dfrac{a}{x^2}+\dfrac{b}{y^2}+\dfrac{c}{z^2}}=\sqrt[3]{a}+\sqrt[3]{b}+\sqrt[3]{c}\)
a) \(\sqrt[3]{5-\sqrt{17}}+\sqrt[3]{5+\sqrt{17}}\)
b) \(\dfrac{1}{\sqrt[3]{4-\sqrt{15}}}+\sqrt[3]{4-\sqrt{15}}\)
c) \(\dfrac{\sqrt[3]{a^4}+\sqrt[3]{a^2b^2}+\sqrt[3]{b^4}}{\sqrt[3]{a^2}+\sqrt[3]{ab}+\sqrt[3]{b^2}}\)
Rút gọn các biểu thức sau
tính giá trị của các biểu thức
a)\(\dfrac{\sqrt[3]{4}+\sqrt[3]{2}+2}{\sqrt[3]{4}+\sqrt[3]{2}+1}\)
b)\(\sqrt{3+\sqrt{3}+\sqrt[3]{10+6\sqrt{3}}}\)
c)\(\dfrac{4+2\sqrt{3}}{\sqrt[3]{10+6\sqrt{3}}}\)
tính
a. \(\dfrac{\sqrt[3]{125}.\sqrt[3]{\dfrac{16}{10}}.\sqrt[3]{-0,5}}{\sqrt[3]{4}+\sqrt[3]{2}+1}\)
b.\(\sqrt[]{3+\sqrt[]{5}+\sqrt[]{10+6\sqrt[]{5}}}\)