Bài 2: Rút gọn biểu thức 1) x(x+2)-2x 2) (2+x)(2-x)+x^2 3) x^2(1-x)+(x+3)(x^2-3x+9) 4) (2x+y)^2+4x^2-4x(2x+y) 5) -2x(x^2-1)+2x(x^2+1) 6) (x-5)(x+3)-x^2-8x+15 7) (4x-1)(2x-3)-2(1-2x)^2 8) 2x^2(x+1)-2x(x^2-5) 9) x^2-2x-(x-7)(x+2) 10) (3x+1)(4x-1)-(2x-3)^2

1) \( x(x+2)-2x \)Rút gọn: \( x^2 + 2x - 2x = x^2 \)2) \( (2+x)(2-x)+x^{2} \)Rút gọn: \( 4 - x^2 + x^2 = 4 \)3) \( x^{2}(1-x)+(x+3)(x^{2}-3x+9) \)Rút gọn: \( x^3 - x^4 + x^3 - 3x^2 + 9x + 3x^2 - 9x + 27 = -x^4 + 2x^3 + 27 \)4) \( (2x+y)^{2}+4x^{2}-4x(2x+y) \)Rút gọn: \( 4x^2 + 4xy + y^2 + 4x^2 - 8x^2 - 4xy = y^2 \)5) \( -2x(x^{2}-1)+2x(x^{2}+1) \)Rút gọn: \( -2x^3 + 2x + 2x^3 + 2x = 4x \)6) \( (x-5)(x+3)-x^{2}-8x+15 \)Rút gọn: \( x^2 - 5x + 3x - x^2 - 8x + 15 = -10x + 15 \)7) \( (4x-1)(2x-3)-2(1-2x)^{2} \)Rút gọn: \( 8x^2 - 12x - 2(4x^2 - 4x + 1) = 8x^2 - 12x - 8x^2 + 8x - 2 = -4x - 2 \)8) \( 2x^{2}(x+1)-2x(x^{2}-5) \)Rút gọn: \( 2x^3 + 2x^2 - 2x^3 + 10x = 2x^2 + 10x \)9) \( x^{2}-2x-(x-7)(x+2) \)Rút gọn: \( x^2 - 2x - x^2 + 7x + 2 = 5x + 2 \)10) \( (3x+1)(4x-1)-(2x-3)^{2} \)Rút gọn: \( 12x^2 - 3x + 4x - 1 - (4x^2 - 12x + 9) = 12x^2 + x - 1 - 4x^2 + 12x - 9 = 8x^2 + 13x - 10 \)