Môn Toán Lớp 8: Rút gọn biểu thức:(2x-1)-(2x+1)-(2x+1)^2-3x(x+2)

Trả Lời

1. (2x-1)-(2x+1)-(2x+1)^2-3x(x+2)

   =2x-1-2x-1-[(2x)^2+2.2x.1+1^2]-3x^2-6x

   =2x-1-2x-1-4x^2-4x-1-3x^2-6x

   =(2x-2x-4x-6x)+(-1-1-1)+(-4x^2-3x^2)

   =-7x^2-10x-3

    

   Trả lời
2. (2x-1) – (2x+1) – (2x+1)^2 – 3x (x+2)

   = 2x – 1 – 2x – 1 – (4x^2+4x+1) – 3x^2 – 6x

   = 2x – 1 – 2x – 1 – 4x^2 – 4x – 1 – 3x^2 – 6x

   =  -(4x^2+3x^2) + (2x-2x-4x-6x) – (1+1+1)

   = -7x^2 – 10x – 3

   Trả lời