1) 3x.(x-1)+(2x-1).(4x+3)-(x-3).(11x+2) 2) (4x+1).(3x-2)-(2x+1).(5x-3)-x.(2x-5) 30/07/2021 Bởi Madelyn 1) 3x.(x-1)+(2x-1).(4x+3)-(x-3).(11x+2) 2) (4x+1).(3x-2)-(2x+1).(5x-3)-x.(2x-5)
Đáp án: $1) 3x(x-1) +(2x-1).(4x+3) -(x-3)(11x+2)$ $ = 3x^2-3x+8x^2+6x-4x-3 -11x^2-2x+33x+6$ $ = (3x^2+8x^2-11x^2) + (-3x+6x-4x-2x+33x) + (-3+6)$ $ = 30x +3$ $2) (4x+1)(3x-2) -(2x+1)(5x-3) -x(2x-5)$ $ = 12x^2-8x+3x-2 -10x^2+6x-5x+3 -2x^2+5x$ $ = (12x^2-10x^2-2x^2)(-8x+3x +6x-5x+5x) + (-2+3)$ $ = x +1$ Bình luận
a) $3x.(x-1)+(2x-1).(4x+3)-(x-3).(11x+2)$ $=3x^2-3x+2x.(4x+3)-(4x+3)-[x.(11x+2)-3.(11x+2)]$ $=3x^2-3x+8x^2+6x-4x-3-[11x^2+2x-33x-6]$ $=11x^2-x-3-11x^2+31x+6$ $=30x+3$ b) $(4x+1).(3x-2)-(2x+1).(5x-3)-x.(2x-5)$ $=4x.(3x-2)+(3x-1)-[2x.(5x-3)+(5x-3)]-2x^2+5x$ $=12x^2-8x+3x-1-[10x^2-6x+5x-3]-2x^2+5x$ $=10x^2-8x-1-10x^2+6x-5x+3+5x$ $=-2x+2$ Bình luận
Đáp án:
$1) 3x(x-1) +(2x-1).(4x+3) -(x-3)(11x+2)$
$ = 3x^2-3x+8x^2+6x-4x-3 -11x^2-2x+33x+6$
$ = (3x^2+8x^2-11x^2) + (-3x+6x-4x-2x+33x) + (-3+6)$
$ = 30x +3$
$2) (4x+1)(3x-2) -(2x+1)(5x-3) -x(2x-5)$
$ = 12x^2-8x+3x-2 -10x^2+6x-5x+3 -2x^2+5x$
$ = (12x^2-10x^2-2x^2)(-8x+3x +6x-5x+5x) + (-2+3)$
$ = x +1$
a) $3x.(x-1)+(2x-1).(4x+3)-(x-3).(11x+2)$
$=3x^2-3x+2x.(4x+3)-(4x+3)-[x.(11x+2)-3.(11x+2)]$
$=3x^2-3x+8x^2+6x-4x-3-[11x^2+2x-33x-6]$
$=11x^2-x-3-11x^2+31x+6$
$=30x+3$
b) $(4x+1).(3x-2)-(2x+1).(5x-3)-x.(2x-5)$
$=4x.(3x-2)+(3x-1)-[2x.(5x-3)+(5x-3)]-2x^2+5x$
$=12x^2-8x+3x-1-[10x^2-6x+5x-3]-2x^2+5x$
$=10x^2-8x-1-10x^2+6x-5x+3+5x$
$=-2x+2$