\(a/4x\left(x-3\right)-3x\left(2+x\right)\\ =4x.x-4x.3-3x.2-3x.x\\ =4x^2-12x-6x-3x^2\\ =x^2-18x\\ b/2x\left(5x+2\right)+\left(2x-3\right)\left(3x-1\right)\\ =2x.5x+2x.2+2x.3x-2x.1-3.3x+3.1\\ =10x^2+4x+6x^2-2x-9x+3\\ =16x^2-7x+3\)

Phần b) = 3

sao bạn ko làm hẳn ra cho bạn ý

1. Thu gọn:

a) 5x. (x-3) - x. (5x+1)

= 5x² - 15x - 5x² - x = -16x

b) -3x. (x-1) - x. (x+1) + 4x. (x-2)

= -3x² + 3x - x² - x + 4x² - 8x

= -6x

a: \(=2x\left(4x^2-4x+1\right)-3x^2-9x-4x^2-4x\)

\(=8x^3-8x^2+2x-7x^2-13x\)

\(=8x^3-15x^2-11x\)

c: \(=5x^3-5x^2-5x^3+5x^2-15=-15\)

d: \(=x^2+10x+25-4x\left(4x^2+12x+9\right)-\left(2x-1\right)\left(x^2-9\right)\)

\(=x^2+10x+25-16x^3-48x^2-36x-\left(2x-1\right)\left(x^2-9\right)\)

\(=-16x^3-47x^2-26x+25-2x^3+18x+x^2-9\)

\(=-18x^3-46x^2-8x+16\)

Bài 1

A= (x-2)(2x-1)-2x(x+3)=2x²-x-4x+2-2x²-6x=-11x+2

Bài 1:

a) \(A=\left(x-2\right)\left(2x-1\right)-2x\left(x+3\right)\)

\(A=2x^2-x-4x+2-2x^2-6x\)

\(A=-11x+2\)

b) \(B=\left(3x-2\right)\left(2x+1\right)-\left(6x-1\right)\left(x+2\right)\)

\(B=6x^2+3x-4x-2-6x^2-12x+x+2\)

\(B=-12x\)

c) \(C=6x\left(2x+3\right)-\left(4x-1\right)\left(3x-2\right)\)

\(C=12x^2+18x-12x^2+8x+3x-2\)

\(C=29x-2\)

d) \(D=\left(2x+3\right)\left(5x-2\right)+\left(x+4\right)\left(2x-1\right)-6x\left(2x-3\right)\)

\(D=10x^2-4x+15x-6+2x^2-x+8x-4-12x^2+18x\)

\(D=36x-10\)

Bài 2: 

a: Ta có: \(2x\left(3x-5\right)\left(x+11\right)-3x\left(2x+3\right)\left(x+7\right)\)

\(=2x\left(3x^2+33x-5x-55\right)-3x\left(2x^2+14x+3x+21\right)\)

\(=6x^3+56x^2-110x-6x^2-51x^2-63x\)

\(=-117x\)

b: Ta có: \(\left(x^2+5x-6\right)\left(x-1\right)-\left(x+2\right)\left(x^2-x+1\right)-x\left(3x-10\right)\)

\(=x^3+4x^2-11x+6-\left(x^3-x^2+x+2x^2-2x+2\right)-3x^2+10x\)

\(=x^3+x^2-x+6-x^3-x^2+x-2\)

=4

c: Ta có: \(\left(x^2+x+1\right)\left(x-1\right)-x^2\left(x+1\right)+x^2-5\)

\(=x^3-1-x^3-x^2+x^2-5\)

=-6

a) 5x² ( 3x² -7x+2)-15x(x-3)

=15x⁴-35x³+10x²-15x²+45x

=15x⁴-35x³-5x²+45x

c) (x+3)(x-3)(x-2)(x+1)

=(x²-9)(x²+x-2x-2)

=(x²-9)(x²-x-2)

=x⁴-x³-2x²-9x²+9x+18

=x⁴-x³-11x²+9x+18

d)(2x+1)²+(4x-1)²+2(2x+1)(4x+1)

=2x²+4x+1-16x²-8x+1

=2x²+4x+1-16x²-8x+1+16x²-4x+8x-2

=2x²+7

e) (2x²-3x)(5x²-2x+1)-10x²(x+3)

=10x⁴ -4x³+2x²-15x³+6x²-3 -10x²-30x

=10x⁴-19x³-2x²-30x-3

thanks bn nka

câu c) bn thíu dấu

Bạn đăng từng bài 1 và tách bài ra cho dễ nhìn hơn nhé! 

3A:

a: =15x^4-5x^2-24x^4+18x^2-6x-6x^4+2x^3

=-15x^4+2x^3+13x^2-6x

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

=1/2x^3-1/5x^2+x-3/4x^3-5/4x^2-x

=-1/4x^3-29/20x^2

c: =3/2x^2(x^2-2x)-2x(x^3+x^2+1)+2(x-1)

=3/2x^4-3x^3-2x^4-2x^3-2x+2x-2

=-1/2x^4-5x^3-2

d: =x^4-2x^3+5x^3-10x^2+5/2x-x^4+x^3-x^2

=4x^3-11x^2+5/2x