Bài 1: Rút gọn
\(3\sqrt{9a^6}-6a^3\) (với mọi a)
\(\sqrt{\left(x-1\right)^2}+\sqrt{\left(1-3x\right)^2}\) (Với \(\dfrac{1}{3}\) < x ≤ 1 )
\(\sqrt{2-\sqrt{3}}.\left(\sqrt{6}+\sqrt{2}\right)\)
\(\left(\sqrt{10}+\sqrt{2}\right)\left(6-2\sqrt{5}\right)\sqrt{3+\sqrt{5}}\)
\(\sqrt{23-8\sqrt{7}}+\sqrt{8-2\sqrt{7}}\)
\(\sqrt{x+2\sqrt{x-1}}+\sqrt{x-2\sqrt{x-1}}\) (với 1<x<2)
\(\sqrt{x+4\sqrt{x-4}}+\sqrt{x-4\sqrt{x-4}}\) (với x ≥4)
a. \(2x^2-8x-3\sqrt{x^2-4x-5}=12\)
b. \(\left(x-3\right)\left(x+2\right)-3\sqrt{x^2-x+1}+9=0\)
c. 12\(-\sqrt{4-3x}=|3x-4|\)
d. \(\sqrt{3x-2}+\sqrt{x-1}=4x-9+2\sqrt{3x^2-5x+2}\)
Giải phương trình:
a. \(3\sqrt{8x}-\sqrt{32x}+\sqrt{50x}=21\)
b. \(\sqrt{25x+50}+3\sqrt{4x+8}-2\sqrt{16x+32}=15\)
c. \(\sqrt{\left(x-2\right)^2}=12\)
d. \(\sqrt{x^2-6x+9}-3=5\)
e.\(\sqrt{\left(2x-1\right)^2}-x=3\)
f. \(\sqrt{3x-6}-x=-2\)
h. \(\sqrt{3-2x}-2=x\)
Giải các phương trình:
a) \(\left(3x-1\right)\left(3x+1\right)=x\left(1+8\sqrt{x+1}\right)\)
b) \(5x^2-5x\sqrt{x^2+x+4}+2x+5=0\)
c) \(9x^2+8x+9=9\left(x+1\right)\sqrt{2x^2+1}\)
d) \(5x^2+2x+2=5x\sqrt{x^2+x+1}\)
e) \(5x^2+20x-12=5\left(x-2\right)\sqrt{3x^2+x}\)
Tính DKXD của các căn bậc thức sau:
a)\(\sqrt{2x-4}\)
b)\(\sqrt{\dfrac{3}{-2x+1}}\)
c)\(\sqrt{\dfrac{-3x+5}{-4}}\)
d)\(\sqrt{-5\left(-2x+6\right)}\)
e)\(\sqrt{\left(x^2+2\right)\left(x-3\right)}\)
f)\(\sqrt{\dfrac{x^2+5}{-x+2}}\)
Rút gọn:
\(A=\frac{x^2+5x+6+x\sqrt{9-x^2}}{3x-x^2+\left(x+2\right).\sqrt{9-x^2}}\)
\(B=\frac{x^2-5x+6+3\sqrt{x^2-6x+8}}{3x-12+\left(x-3\right).\sqrt{x^2-6x+8}}\)
\(C=\frac{\sqrt{2\sqrt{4-x^2}}.\left(\sqrt{\left(2+x\right)^3}-\sqrt{\left(2-x\right)^3}\right)}{4+\sqrt{4-x^2}}\)
Giải các phương trình sau:
a. \(\sqrt{25x+75}+3\sqrt{x-2}=2\sqrt{x-2}+\sqrt{9x-18}\)
b. \(\sqrt{\left(2x-1\right)^2}=4\)
c. \(\sqrt{\left(2x+1\right)^2}=3x-5\)
d. \(\sqrt{4x-12}-14\sqrt{\dfrac{x-2}{49}}=\sqrt{9x-18}+8\)
Giải các phương trình sau:
a) \(x^3-6x^2+28x-25=2\left(x+1\right)\sqrt{x+2}+\left(2x-1\right)\sqrt{x-1}\)
b) \(x^3-4x^2+31x-15=2\left(x+2\right)\sqrt{3x+1}+x\sqrt{2x-1}\)
c) \(5x^2+4x+4=2\left(x+2\right)\sqrt{x+3}+x\sqrt{3x-2}\)
\(\sqrt[3]{x^2-1}+\sqrt{3x^3-2}=3x-2\)
\(\sqrt{\left(2-x\right)\left(5-x\right)}=x+\sqrt{\left(2-x\right)\left(10-x\right)}\)