7
3
Giải hộ mk đến câu 6 aj hứa sẽ vote 5sao mk đang cần gấp
Hãy luôn nhớ cảm ơn và vote 5*
nếu câu trả lời hữu ích nhé!
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`1.`
`(x+2)/(x-2)-5/x=8/(x^2-2x)` `(ĐKXĐ: x≠0,x≠2)`
`⇔( x(x+2)-5(x-2) )/( x(x-2) )=8/( x(x-2) )`
`⇔x(x+2)-5(x-2)=8`
`⇔x^2+2x-5x+10-8=0`
`⇔x^2-3x+2=0`
`⇔x^2-x-2x+2=0`
`⇔x(x-1)-2(x-1)=0`
`⇔(x-1)(x-2)=0`
`⇔ [(x-1=0),(x-2=0):}`
`⇔ [(\text{x=1 (tm) } ),(\text{x=2 (ktm) } ):}`
Vậy `S={1}`
`2.`
`(x-1)/x+1/(x+1)=(2x+1)/(x^2+x)` `(ĐKXĐ: x≠0,x≠-1)`
`⇔( (x-1)(x+1) + x )/( x(x+1) )= (2x+1)/( x(x+1) )`
`⇔ (x-1)(x+1)+x=2x+1`
`⇔x^2-1+x-2x-1=0`
`⇔x^2+x-2x-2=0`
`⇔x(x+1)-2(x+1)=0`
`⇔(x+1)(x-2)=0`
`⇔ [(x+1=0),(x-2=0):}`
`⇔ [(\text{x=-1 (ktm) } ),(\text{x=2 (tm) } ):}`
Vậy `S={2}`
`3.`
`(x-7)/x=49/( x(x-7) )+ (3x)/(x-7)` `(ĐKXĐ: x≠0,x≠7)`
`⇔( (x-7)^2 )/( x(x-7) ) = ( 49+3x^2 )/( x(x-7) )`
`⇔ (x-7)^2=49+3x^2`
`⇔x^2-14x+49=49+3x^2`
`⇔x^2-14x=3x^2`
`⇔2x^2+14=0`
`⇔2x(x+7)=0`
`⇔ [(x=0),(x+7=0):}`
`⇔ [(\text{x=0 (ktm) } ),(\text{x=-7 (tm) } ):}`
Vậy `S={-7}`
`4.`
`(x+1)/(x-1)-(3x+1)/(x^2-x)=1/x` `(ĐKXĐ: x≠0,x≠1)`
`⇔( x(x+1)-(3x+1) )/( x(x-1) )= (x-1)/( x(x-1) )`
`⇔x(x+1)-(3x+1)=x-1`
`⇔x^2+x-3x-1-x+1=0`
`⇔x^2-3x=0`
`⇔x(x-3)=0`
`⇔ [(x=0),(x-3=0):}`
`⇔ [(\text{x=0 (ktm) } ),(\text{x=3 (tm) } ):}`
Vậy `S={3}`
`5.`
`(5+x)/(3x-6)-(2x-3)/(2x-4)=1/2` `(ĐKXĐ: x≠2)`
`⇔(x+5)/( 3(x-2) ) +(3-2x)/( 2(x-2) )=1/2`
`⇔( 2(x+5) )/( 6(x-2) ) + ( 3(3-2x) )/( 6(x-2) )= ( 3(x-2) )/( 6(x-2) )`
`⇔2(x+5)+3(3-2x)=3(x-2)`
`⇔2x+10+9-6x=3x-6`
`⇔2x-6x-3x=-6-10-9`
`⇔-7x=-25`
`⇔x=25/7` `(tm)`
Vậy `S={25/7}`
`6.`
`(6x-x^2)/(x^2-2x)+x/(x-2)=3/x` `(ĐKXĐ: x≠0,x≠2)`
`⇔( 6x-x^2 + x^2)/( x(x-2) )= ( 3(x-2) )/( x(x-2) )`
`⇔6x-x^2+x^2=3(x-2)`
`⇔6x=3x-6`
`⇔3x=-6`
`⇔x=-2` `(tm)`
Vậy `S={-2}`
`#` `ccUh`
Hãy giúp mọi người biết câu trả lời này thế nào?
20165
13409
Đáp án+Giải thích các bước giải:
`1)`
`\frac{x+2}{x-2}-5/x=\frac{8}{x^{2}-2x}`
`(đk:x\ne0;x\ne2)`
`<=>\frac{x.(x+2)}{x.(x-2)}-\frac{5.(x-2)}{x.(x-2)}=\frac{8}{x.(x-2)}`
`=>x.(x+2)-5.(x-2)=8`
`<=>x^{2}+2x-5x+10=8`
`<=>x^{2}-3x+10-8=0`
`<=>x^{2}-x-2x+2=0`
`<=>x.(x-1)-2.(x-1)=0`
`<=>(x-1).(x-2)=0`
`<=>x-1=0` hoặc `x-2=0`
`<=>x=1(tmđk)` hoặc `x=2(ktmđk)`
`<=>x=1`
Vậy `S={1}.`
`2)`
`\frac{x-1}{x}+\frac{1}{x+1}=\frac{2x+1}{x^{2}+x}`
`(đk:x\ne0;x\ne-1)`
`<=>\frac{(x-1).(x+1)}{x.(x+1)}+\frac{x}{x.(x+1)}=\frac{2x+1}{x.(x+1)}`
`=>x^{2}-1^{2}+x=2x+1`
`<=>x^{2}+x-1-2x-1=0`
`<=>x^{2}-x-2=0`
`<=>x^{2}-2x+x-2=0`
`<=>x.(x-2)+1.(x-2)=0`
`<=>(x+1).(x-2)=0`
`<=>x+1=0` hoặc `x-2=0`
`<=>x=-1(ktmđk)` hoặc `x=2(tmđk)`
`<=>x=2`
Vậy `S={2}.`
`3)`
`\frac{x-7}{x}=\frac{49}{x.(x-7)}+\frac{3x}{x-7}`
`(đk:x\ne0;x\ne7)`
`<=>\frac{(x-7).(x-7)}{x.(x-7)}=\frac{49}{x.(x-7)}+\frac{3x.x}{x.(x-7)}`
`=>x^{2}-7x-7x+49=49+3x^{2}`
`<=>3x^{2}+49-x^{2}+14x-49=0`
`<=>2x^{2}+14x=0`
`<=>2x.(x+7)=0`
`<=>2x=0` hoặc `x+7=0`
`<=>x=0(ktmđk)` hoặc `x=-7(tmđk)`
`<=>x=-7`
Vậy `S={-7}`
`4)`
`\frac{x+1}{x-1}-\frac{3x+1}{x^{2}-x}=1/x`
`(đk:x\ne0;x\ne1)`
`<=>\frac{x.(x+1)}{x.(x-1)}-\frac{3x+1}{x.(x-1)}=\frac{x-1}{x.(x-1)}`
`=>x^{2}+x-3x-1=x-1`
`<=>x^{2}-2x-1-x+1=0`
`<=>x^{2}-3x=0`
`<=>x.(x-3)=0`
`<=>x=0(ktmđk)` hoặc `x-3=0`
`<=>x=3`
Vậy `S={3}`
`5)`
`\frac{5+x}{3x-6}-\frac{2x-3}{2x-4}=1/2`
`(đk:x\ne2)`
`<=>\frac{x+5}{3.(x-2)}-\frac{2x-3}{2.(x-2)}=1/2`
`<=>\frac{2.(x+5)}{6.(x-2)}-\frac{3.(2x-3)}{6.(x-2)}=\frac{3.(x-2)}{6.(x-2)}`
`=>2x+10-6x+9=3x-6`
`<=>-4x+19-3x+6=0`
`<=>-7x+25=0`
`<=>-7x=-25`
`<=>x=25/7(tmđk)`
Vậy `S={25/7}.`
`6)`
`\frac{6x-x^{2}}{x^{2}-2x}+\frac{x}{x-2}=3/x`
`(đk:x\ne0;x\ne2)`
`<=>\frac{6x-x^{2}}{x.(x-2)}+\frac{x.x}{x.(x-2)}=\frac{3.(x-2)}{x.(x-2)}`
`=>6x-x^{2}+x^{2}=3x-6`
`<=>3x-6=6x`
`<=>3x-6x=6`
`<=>-3x=6`
`<=>x=-2(tmđk)`
Vậy `S={-2}.`
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Bảng tin
20165
196865
13409
Cô lên e 10 câu nữa thôi:V
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thanks a-)