1/ Tim x
a/x.(x+5) - (x-2)^2 = 4
b/ x.( x+5 ) ( x-5)- (x+2)(x^2 - 2x +4)= 3
c/(x-2)^2 -x (x-8)=12
d/(x-2)^2 -(x+2)^2=11
e/x^2 + 8x -9 = 0
Giai nhanh ho mk nhe
Mk camon
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a: =>x(x+2)=x+2 và x(x+2)=-(x+2)
=>(x+2)(x+1)=0 hoặc (x+2)(x-1)=0
=>\(x\in\left\{-2;-1;1\right\}\)
b: TH1: x<-5/3
=>1-2x+3x+5=3
=>x+6=3
=>x=-3(nhận)
TH2: -5/3<=x<1/2
=>1-2x-3x-5=3
=>-5x-4=3
=>-5x=7
=>x=-7/5(nhận)
TH3: x>=1/2
=>2x-1-3x-5=3
=>-x-6=3
=>-x=9
=>x=-9(loại)
c: =>(2x-2)^2-(3x-6)^2=0
=>(2x-2-3x+6)(2x-2+3x-6)=0
=>(-x+4)(5x-8)=0
=>x=8/5 hoặc x=4
a: \(=\dfrac{x^2+3x+2-x^2+2x+8}{\left(x-2\right)\left(x+2\right)}=\dfrac{5x+10}{\left(x-2\right)\left(x+2\right)}=\dfrac{5}{x-2}\)
b: \(=\dfrac{x^2-4x+3-x^2-3x-2+8x}{\left(x-1\right)\left(x+1\right)}=\dfrac{x+1}{\left(x-1\right)\left(x+1\right)}=\dfrac{1}{x-1}\)
c: \(=\dfrac{x+2}{x\left(x-2\right)}+\dfrac{2}{x\left(x+2\right)}+\dfrac{3x+2}{\left(x+2\right)\left(x-2\right)}\)
\(=\dfrac{x^2+2x+2x-4+3x+2}{x\left(x-2\right)\left(x+2\right)}=\dfrac{x^2+7x-2}{x\left(x-2\right)\left(x+2\right)}\)
a,
\(\dfrac{x+1}{x-2}-\dfrac{x}{x+2}+\dfrac{8}{x^2-4}\\ =\dfrac{x^2+3x+2-x^2+2x+8}{\left(x-2\right)\left(x+2\right)}=\dfrac{5x+10}{\left(x-2\right)\left(x+2\right)}=\dfrac{5\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}=\dfrac{5}{x-2}\)
b,
\(\dfrac{x-3}{x+1}-\dfrac{x+2}{x-1}+\dfrac{8x}{x^2-1}\\ =\dfrac{x^2-4x+3-x^2-3x-2+8x}{\left(x-1\right)\left(x+1\right)}=\dfrac{x+1}{\left(x-1\right)\left(x+1\right)}\\ =\dfrac{1}{x-1}\)
a: =(x^2+x)^2+3(x^2+x)-10
=(x^2+x+5)(x^2+x-2)
=(x^2+x+5)(x+2)(x-1)
b: (x^2+2x)^2-2(x^2+2x)-3
=(x^2+2x-3)(x^2+2x+1)
=(x+1)^2*(x+3)(x-1)
c: =(x^2+x)^2+4(x^2+x)-12
=(x^2+x+6)(x^2+x-2)
=(x^2+x+6)(x+2)(x-1)
d: =(x^2+10x+16)(x^2+10x+24)+16
=(x^2+10x)^2+40(x^2+10x)+400
=(x^2+10x+20)^2
nguyenthihuyentrang
( 2x - 5)2 - ( 4x - 1 ) ( x + 3 ) = 5
=> ( 2x ) 2 - 2 . 2x. 5 + 52 - 4x2 + 12x - 3 - x = 5
=> 4x2 - 20x + 15 - 4x2 + 11x - 3 = 5
=> -20x + 11x = 5 + 3 - 15
=> -9x = -7 => x = 7/9
^^ Học tốt!
a) (x-2)3+6(x+1)2-x3+12=0
\(\Rightarrow\)x3-6x2+12x-8+6(x2+2x+1)-x3+12=0
\(\Rightarrow\)x3-6x2+12x-8+6x2+12x+6-x3+12=0
\(\Rightarrow\)24x+10=0
\(\Rightarrow\)24x=-10
\(\Rightarrow\)x=\(\dfrac{-10}{24}=\dfrac{-5}{12}\)
b)(x-5)(x+5)-(x+3)2+3(x-2)2=(x+1)2-(x-4)(x+4)+3x2
\(\Rightarrow\)x2-25-(x2+6x+9)+3(x2-4x+4)=x2+2x+1-(x2-16)+3x2
\(\Rightarrow\)x2-25-x2-6x-9+3x2-12x+12=x2+2x+1-x2+16+3x2
\(\Rightarrow\)3x2-18x-22=3x2+2x+17
\(\Rightarrow\)3x2-18x-22-3x2-2x-17=0
\(\Rightarrow\)-20x-39=0
\(\Rightarrow\)-20x=39
\(\Rightarrow\)x=\(-\dfrac{39}{20}\)
một đòn bẫy dài một mét .đặt ở đâu để có thể dùng 3600n có thể nâng tảng đá nặng 120kg?