Toán Lớp 8: Tìm x: `x^3-2x^2+x=0` Thực Hiện phép tinh: `(x+2)(x-2)+2x(1-1/2 x)`

Question

Toán Lớp 8:  Tìm x:  x^3-2x^2+x=0 Thực Hiện phép tinh:  (x+2)(x-2)+2x(1-1/2 x)

thienthanh · Answer

x&sup3; - 2x&sup2; + x = 0   x(x&sup2; - 2x + 1) = 0   x(x-1)&sup2; = 0   &rArr; ( left[  begin{array}{l}x=0  (x-1)^2 = 0 end{array}  right. )    &rArr;  ( left[  begin{array}{l}x=0  x-1= 0 end{array}  right. )    &rArr;  ( left[  begin{array}{l}x=0  x = 1 end{array}  right. )    Vậy  ( left[  begin{array}{l}x=0  x = 1 end{array}  right. )      ----------------------------   (x+2)(x-2) + 2x(1- 1/2  x)   =x&sup2; - 4 + 2x .  -  x.x   =2x - 4

buithaianh98 · Answer

Giải đáp:    T&igrave;m x:     x^(3)-2x^(2)+x=0   &hArr;x.x^(2)-x.2x+x.1=0   &hArr;x.(x^(2)-2x+1)=0   &hArr;x.(x-1)^2=0   &hArr;x.(x-1)=0   $&hArr; left[ begin{matrix}x=0   x-1=0 end{matrix} right.$   $&hArr; left[ begin{matrix}x=0   x=1 end{matrix} right.$   Vậy x&isin;{0;1}    Thực hiện ph&eacute;p t&iacute;nh:     (x+2)(x-2)+2x(1-1/2x)     =x^(2)-4+2x-x^2     =2x-4