Question

Tìm x biết a) (x^2-4x+5)_(x^2-2x+1)=3 lớp 7

b)(4x^3-5X^2+3x-1)+(3-5x+5x^2-4x^3)=2

c)(3x-2)-(5x+4)=(x-3)-(X+5)

Answer 1

a, \(-4x+5+2x-1=3\Leftrightarrow-2x=-1\Leftrightarrow x=\dfrac{1}{2}\)

b, \(-2x+2=2\Leftrightarrow x=0\)

c, \(-2x-6=-8\Leftrightarrow x=1\)

Answer 2

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

`=> x^2 - 4x + 5 - x^2 + 2x - 1 = 3`

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

`=> -2x + 4 =3`

`=> -2x = 3-4`

`=> -2x = -1`

`=>x = -1 : -2`

`=> x = 1/2`

Vậy `x=1/2`