Sossssssss . Giải nhanh giúp em với ak

Tặng 5 sao cho câu trả lời ak

`a)`

`x(x+2)-x^2=4`

`x^2+2x-x^2=4`

`2x=4`

`x=2`

Vậy `x=2`

`b)`

`(x+2)(x+3)-x^2=5-2x`

`x^2+2x+3x+6-x^2=5-2x`

`x^2+5x+6-x^2=5-2x`

`5x+6=5-2x`

`5x+2x=5-6`

`7x=-1`

`x=-1/7`

Vậy `x=-1/7`

`c)`

`(x-1)(x+2)-(x+3)(x+4)=5`

`x^2-x+2x-2-(x^2+3x+4x+12)=5`

`x^2+x-2-(x^2+7x+12)=5`

`x^2+x-2-x^2-7x-12=5`

`-6x-14=5`

`-6x=19`

`x=-19/6`

Vậy `x=-19/6`

`d)`

`x^2+5x+6=0`

`x^2+3x+2x+6=0`

`x(x+3)+2(x+3)=0`

`(x+2)(x+3)=0`

`x+2=0` hoặc `x+3=0`

`x=-2` hoặc `x=-3`

Vậy `x in {-2;-3}`

`e)`

`x^2-9x-10=0`

`x^2+x-10x-10=0`

`x(x+1)-10(x+1)=0`

`(x-10)(x+1)=0`

`x-10=0` hoặc `x+1=0`

`x=10` hoặc `x=-1`

Vậy `x in {10;-1}`

`f)`

`2x^2+5x-7=0`

`2x^2-2x+7x-7=0`

`2x(x-1)+7(x-1)=0`

`(2x+7)(x-1)=0`

`2x+7=0` hoặc `x-1=0`

`x=-7/2` hoặc `x=1`

Vậy `x in {-7/2;1}`

`g)`

`3x^2+5x-8=0`

`3x^2-3x+8x-8=0`

`3x(x-1)+8(x-1)=0`

`(3x+8)(x-1)=0`

`3x+8=0` hoặc `x-1=0`

`x=-8/3` hoặc `x=1`

Vậy `x in {-8/3;1}`