Phân tích ra thừa số:
a, x - 9 với x > 0
b, x - 5\(\sqrt{x}\) + 4
d, x-2\(\sqrt{x-1}\) - a2
đưa thừa số ra ngoài dấu căn :
a) a2\(\sqrt{\dfrac{2}{3a}}\)( a > 0 )
b) \(\dfrac{x-3}{x}\)\(\sqrt{\dfrac{x^3}{9-x^2}}\)(0<x<3)
a: \(a^2\cdot\sqrt{\dfrac{2}{3a}}=a^2\cdot\dfrac{\sqrt{2}}{\sqrt{3}\cdot\sqrt{a}}=\dfrac{a\sqrt{2}}{\sqrt{3}}=\dfrac{a\sqrt{6}}{3}\)
b: \(\dfrac{x-3}{x}\cdot\sqrt{\dfrac{x^3}{9-x^2}}\)
\(=\dfrac{x-3}{x}\cdot\dfrac{x\sqrt{x}}{\sqrt{x-3}\cdot\sqrt{x+3}}\)
\(=\dfrac{\sqrt{x}\cdot\sqrt{x-3}}{\sqrt{x+3}}\)
Phân tích ra thừa số:
a) x - 9 với x > 0 ; \(\text{ b) x - 5\sqrt{x}+ 4 ;}\)
\(\text{c) 6√xy - 4x\sqrt{x} - 9y√y + 6xy ; }\) \(\text{ d) x - 2\sqrt{x-1} - a^2}\)
a)x-9=\(\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)\)
Phân tích ra thừa số:
A=x-7, với x>0
C=5+4x, với x<0
D=x2 -2|x|-1
B=x2-2\(\sqrt{3x}+3\)
Câu 3: Phân tích ra thừa số:
a. \(\sqrt{xy}-x\)
b. \(x+y-2\sqrt{xy}\)
c. \(x\sqrt{y}-y\sqrt{x}\)
d. \(\sqrt{xy}+2\sqrt{x}-3\sqrt{y}-6\)
\(a,=\sqrt{x}\left(\sqrt{y}-\sqrt{x}\right)\\ b,=\left(\sqrt{x}-\sqrt{y}\right)^2\\ c,=\sqrt{xy}\left(\sqrt{x}-\sqrt{y}\right)\\ d,=\sqrt{x}\left(\sqrt{y}+2\right)-3\left(\sqrt{y}+2\right)\\ =\left(\sqrt{x}-3\right)\left(\sqrt{y}+2\right)\)
1. Phân tích ra thừa số
a.\(\sqrt{ab}-\sqrt{ac}+\sqrt{bc}+b\)
b.x-y-3(\(\sqrt{x}-\sqrt{y}\))
c. \(\sqrt{x^2-y^2}\)-x+y
2. GPT
a.\(\sqrt{\sqrt{5}-\sqrt{3}x}\)=\(\sqrt{8+2\sqrt{15}}\)
b.\(\sqrt{2+\sqrt{3+\sqrt{x}}}=3\)
Bài 2:
a: Ta có: \(\sqrt{\sqrt{5}-x\sqrt{3}}=\sqrt{8+2\sqrt{15}}\)
\(\Leftrightarrow\sqrt{5}-x\sqrt{3}=8+2\sqrt{15}\)
\(\Leftrightarrow x\sqrt{3}=\sqrt{5}-8-2\sqrt{15}\)
\(\Leftrightarrow x=\dfrac{\sqrt{15}-8\sqrt{3}-6\sqrt{5}}{3}\)
b: Ta có: \(\sqrt{2+\sqrt{\sqrt{x}+3}}=3\)
\(\Leftrightarrow\sqrt{\sqrt{x}+3}=7\)
\(\Leftrightarrow\sqrt{x}=46\)
hay x=2116
Bài 4: Phân tích thành nhân tử:
a) x – 1 với x > 0 b) x – 5 với x > 0
c) \(x+2\sqrt{xy}+y\)với\(x,y\ge0\) d) \(x-4\sqrt{x}\sqrt{y}+4y\)
Bài 5: Giải các phương trình sau:
a) \(\sqrt{9\left(x-1\right)}+\sqrt{4\left(x-1\right)}-\frac{4}{5}\sqrt{25\left(x-1\right)}=1\)
b) \(\frac{1}{3}\sqrt{9\left(x-5\right)}+\frac{1}{2}\sqrt{4\left(x-5\right)}-\frac{7}{5}\sqrt{25\left(x-5\right)}=2\)
c) \(\sqrt{x}+\frac{9}{\sqrt{x}}=6\)
b4 :
\(a,x-1=\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)\)
\(b,x-5=\left(\sqrt{x}-\sqrt{5}\right)\left(\sqrt{x}+\sqrt{5}\right)\)
\(c,x+2\sqrt{xy}+y=\left(\sqrt{x}+\sqrt{y}\right)^2\)
\(d,x-4\sqrt{x}\sqrt{y}+4y=\left(\sqrt{x}-2\sqrt{y}\right)^2\)
b5:
\(a,ĐK:x\ge1\)
\(\sqrt{9\left(x-1\right)}+\sqrt{4\left(x-1\right)}-\frac{4}{5}\sqrt{25\left(x-1\right)}=1\)
\(\Leftrightarrow3\sqrt{x-1}+2\sqrt{x-1}-4\sqrt{x-1}=1\)
\(\Leftrightarrow\sqrt{x-1}=1\)
\(\Leftrightarrow x=2\left(tm\right)\)
\(b,ĐK:x\ge5\)
\(\frac{1}{3}\sqrt{9\left(x-5\right)}+\frac{1}{2}\sqrt{4\left(x-5\right)}-\frac{7}{5}\sqrt{25\left(x-5\right)}=2\)
\(\Leftrightarrow\sqrt{x-5}+\sqrt{x-5}-7\sqrt{x-5}=2\)
\(\Leftrightarrow-5\sqrt{x-5}=2\)
\(\Leftrightarrow\sqrt{x-5}=-\frac{2}{5}\left(voli\right)\)
\(c,ĐK:x>0\)
\(\sqrt{x}+\frac{9}{\sqrt{x}}=6\)
\(\Leftrightarrow x+9=6\sqrt{x}\)
\(\Leftrightarrow x-6\sqrt{x}+9=0\)
\(\Leftrightarrow\left(\sqrt{x}-3\right)^2=0\)
\(\Leftrightarrow x=9\left(tm\right)\)
\(\sqrt{48.45}\) Đưa thừa số ra ngoài dấu căn:
\(\sqrt{225.17}\)
\(\sqrt{a^3b^7}với\) \(a\ge0;b\ge0\)
\(\sqrt{x^5\left(x-3\right)^2}\) với \(x>0\)
\(\sqrt{48\cdot45}=12\sqrt{15}\\ \sqrt{225\cdot17}=15\sqrt{17}\\ \sqrt{a^3b^7}=\left|ab^3\right|\sqrt{ab}=ab^3\sqrt{ab}\\ \sqrt{x^5\left(x-3\right)^2}=\left|x^2\left(x-3\right)\right|\sqrt{x}=x^2\left(x-3\right)\sqrt{x}\)
\(\sqrt{48\cdot45}=4\sqrt{3}\cdot3\sqrt{5}=12\sqrt{15}\)
\(\sqrt{225\cdot17}=15\sqrt{17}\)
Đưa thừa số ra ngoài dấu căn:
a) $\sqrt{28 x^{4} y^{2}}$ với $y \leq 0$;
b) $\sqrt{63 a^{2} b^{4}}$ với $a \geq 0$;
c) $\sqrt{147(a-1)^{3}}$;
d) $\sqrt{192(y+2)^{5}}$.
a, -2x^2y căn 7
b, ab^2 căn 63
c, a-1 căn 147a-147
d, y+2 nhân căn [192 nhân (y+2)^3]
a)-2x²y√7
b) 3ab²√7
c) 7(a-1)√3(a-1)
d) 8(y+2)²√3(y+2)
Phân tích ra thừa số :
a)2018 - x với x>0
b)2018 +x với x<0
c)\(7x-12\sqrt{x}+5\)
d)\(43+3\sqrt{7}-2\sqrt{5}\)
e)x\(x\sqrt{x}+y\sqrt{y}+\sqrt{x}+\sqrt{y}\)
a: \(2018-x=\left(\sqrt{2018}-\sqrt{x}\right)\left(\sqrt{2018}+\sqrt{x}\right)\)
b: \(2018+x=2018-\left(-x\right)=\left(\sqrt{2018}-\sqrt{-x}\right)\left(\sqrt{2018}+\sqrt{-x}\right)\)
c: \(7x-12\sqrt{x}+5\)
\(=7x-7\sqrt{x}-5\sqrt{x}+5\)
\(=\left(\sqrt{x}-1\right)\left(7\sqrt{x}-5\right)\)