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a: A=căn x-1
=>\(\left(\sqrt{x}-1\right)\cdot\dfrac{\sqrt{x}}{3}-\left(\sqrt{x}-1\right)=0\)
=>(căn x-1)(1/3*căn x-1)=0
=>x=1 hoặc x=9
b: \(B=\dfrac{x+2\sqrt{x}+4-x+\sqrt{x}-1}{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}\)
\(=\dfrac{3\left(\sqrt{x}+1\right)}{\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)}=\dfrac{3}{x-\sqrt{x}+1}\)
c: \(A\cdot B< =\dfrac{\sqrt{x}-1}{x-\sqrt{x}+1}\)
=>\(\dfrac{3\left(x-\sqrt{x}\right)}{3\left(x-\sqrt{x}+1\right)}< =\dfrac{\sqrt{x}-1}{x-\sqrt{x}+1}\)
=>x-2căn x+1<=0
=>(căn x-1)^2<=0
=>x=1
a:=>(x-3)(2x-5)=0
=>x=3 hoặc x=5/2
b: =>(x-2)(x+2)+(x-2)(2x-3)=0
=>(x-2)(x+2+2x-3)=0
=>(x-2)(3x-1)=0
=>x=1/3 hoặc x=1
c: =>(2x+5-x-2)(2x+5+x+2)=0
=>(x+3)(3x+7)=0
=>x=-7/3 hoặc x=-3
d: =>(x-2)(x-3)=0
=>x=2 hoặc x=3
e: =>(x+3)(x^2-3x+9+x-9)=0
=>(x+3)(x^2-2x)=0
=>\(x\in\left\{0;2;-2\right\}\)
f: =>(10x-5)^2=(2x-4)^2
=>(10x-5-2x+4)(10x-5+2x-4)=0
=>(8x-1)(12x-9)=0
=>x=3/4 hoặc x=1/8
Vì \(RN=NQ,QM=QP\Rightarrow MN\) là đường trung bình tam giác PQR
\(\Rightarrow PQ=2MN=2.22,125=44,25\)
\(\left(2x-5\right).2=\left(x+2\right).3\)
\(\Rightarrow4x-10=3x+6\)
\(\Rightarrow x=16\)
\(\dfrac{2x+5}{3}=\dfrac{x+2}{2}\)
MTC : 6
Quy đồng mẫu thức :
\(\Rightarrow\) \(\dfrac{2\left(2x+5\right)}{6}=\)\(\dfrac{3\left(x+2\right)}{6}\)
Suy ra : 2(2x + 5) = 3(x + 2)
\(\Leftrightarrow\) 4x + 10 = 3x + 6
\(\Leftrightarrow\) 4x + 10 - 3x - 6 = 0
\(\Leftrightarrow\) x + 4 = 0
\(\Leftrightarrow\) x = - 4
Vậy S = \(\left\{-4\right\}\)
Chúc bạn học tốt
`(3x+2)/3 <= (x-4)/7`
`<=>7(3x+2) <= 3(x-4)`
`<=>21x+14 <= 3x-12`
`<=> 18x <=-26`
`<=>x <= -13/9`
Vậy `x<=-13/9`.
`(3x+2)/3 <= (x-4)/7`
`<=>7(3x+2) <= 3(x-4)`
`<=> 21x+14<=3x-12`
`<=>18x <= -26`
`<=> x <=-13/9`
ĐK: ` x\ne \pm 3`
`(x+1)/(x-3)+(x-1)/(x+3)=(x+6)/(x^2-9)`
`<=>(x+1)(x+3)+(x-1)(x-3)=x+6`
`<=>x^2+4x+3+x^2-4x+3=x+6`
`<=>2x^2+6=x+6`
`<=>2x^2-x=0`
`<=>x(2x-1)=0`
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{1}{2}\end{matrix}\right.\)
Vậy `S={0; 1/2}`.
ĐKXĐ: x ≠ -3, x ≠ 3
\(\dfrac{x+1}{x-3}+\dfrac{x-1}{x+3}=\dfrac{x+6}{x^2-9}\)
\(\Leftrightarrow\dfrac{\left(x+1\right)\left(x+3\right)+\left(x-1\right)\left(x-3\right)}{\left(x-3\right)\left(x+3\right)}=\dfrac{x+6}{\left(x-3\right)\left(x+3\right)}\)
\(\Rightarrow x^2+4x+3+x^2-4x+3=x+6\)
\(\Leftrightarrow2x^2-x=0\)
\(\Leftrightarrow x\left(2x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\left(tm\right)\\x=\dfrac{1}{2}\left(tm\right)\end{matrix}\right.\)
Vậy...
Bài 3:
a: Ta có: \(4x\left(x+1\right)=8\left(x+1\right)\)
\(\Leftrightarrow\left(x+1\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\)
b: Ta có: \(x\left(x-1\right)+2\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-2\end{matrix}\right.\)
c: Ta có: \(2x\left(x-2\right)-\left(x-2\right)^2=0\)
\(\Leftrightarrow\left(x-2\right)\left(2x-x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
2a) (3x-5y)(x+1)
b) (3x-2)(x-6)
c) (4y+1)(x-1)
d) (x-2)(x-3)(x-4)
e) (7x+1)(x-y)