`G(x)+H(x)=(21x^2+1+17x)+(-2+6x^3-12x^2-8)`

`=21x^2+1+17x-2+6x^3-12x^2-8`

`= 6x^3+(21x^2-12x^2)+17x+(1-2-8)`

`= 6x^3+9x^2+17x-9`

`G(x)-H(x)=(21x^2+1+17x)-(-2+6x^3-12x^2-8)`

`= 21x^2+1+17x+2-6x^3+12x^2+8`

`= -6x^3+(21x^2+12x^2)+17x+(1+2+8)`

`= -6x^3+33x^2+17x+11`

`----`

`M(x)+N(x)=(7x^5 + 1 + 17x^4 - 2)+(6x^4 - 12x^2 - 23x^4 + x)`

`= 7x^5 + 1 + 17x^4 - 2+6x^4 - 12x^2 - 23x^4 + x`

`= 7x^5+(17x^4+6x^4-23x^4)-12x^2+x+(1-2)`

`= 7x^5-12x^2+x-1`

`M(x)-N(x)=(7x^5 + 1 + 17x^4 - 2)-(6x^4 - 12x^2 - 23x^4 + x)`

`= 7x^5 + 1 + 17x^4 - 2-6x^4 + 12x^2 + 23x^4 - x`

`= 7x^5+(17x^4-6x^4+23x^4)+12x^2-x+(1-2)`

`= 7x^5+34x^4+12x^2-x-1`

Mình đã trl rồi nha!

(https://hoc24.vn/cau-hoi/tinh-tong-avf-hieu-cac-da-thuc-saugx-21x2-1-17x-va-hx-2-6x3-12x2-8mx-7x5-1-17x4-2-va-nx-6x4-12x2-23x4-x.7858748287383)

a: \(=\dfrac{6x^2+9x+8x+12}{2x+3}=\dfrac{3x\left(2x+3\right)+4\left(2x+3\right)}{2x+3}\)

=3x+4

b: \(=\dfrac{5x^2-2x+15x-6}{5x-2}\)

\(=\dfrac{x\left(5x-2\right)+3\left(5x-2\right)}{5x-2}=x+3\)

c: \(=\dfrac{-8x^2+20x+2x-5-10}{2x-5}=-4x+1+\dfrac{-10}{2x-5}\)

d: \(=\dfrac{14x^2-35x+2x-5}{2x-5}=\dfrac{7x\left(2x-5\right)+\left(2x-5\right)}{2x-5}\)

=7x+1

e: \(=\dfrac{2x^3+x^2+6x^2+3x+12x+6}{2x+1}\)

\(=\dfrac{x^2\left(2x+1\right)+3x\left(2x+1\right)+6\left(2x+1\right)}{2x+1}=x^2+3x+6\)

f: \(=\dfrac{x^3-2x^2+6x^2-12x+x-2}{x-2}=x^2+6x+1\)

g: \(=\dfrac{12x^3+6x^2-4x^2-2x+6x+3}{2x+1}=6x^2-2x+3\)

huhu , ai rảnh thì làm giúp mk vs ạ !!!

a)  \(x^3+8x^2+17x+10\)

\(=x^2\left(x+1\right)+7x\left(x+1\right)+10\left(x+1\right)\)

\(=\left(x+1\right)\left(x^2+7x+10\right)\)

\(=\left(x+1\right)\left(x+2\right)\left(x+5\right)\)

b)  \(=x^4-2x^3-12x^2+12x+36\)

\(=x^2\left(x^2-2x-6\right)-2\left(x^2-2x-6\right)\)

\(=\left(x^2-2\right)\left(x^2-2x-6\right)\)

A, 7[x + 5] - 20 = 190

7x + 35 - 20 = 190

7x + 15 = 190

7x = 175

x = 25

B, 155 - 10[x + 1] = 55

155 - 10x - 10 = 55

-10x + 90 = 55

-10x = -35

x = 3.5

C, 6[x + 2^3] + 40 = 100

6[x + 8] + 40 = 100

6x + 48 + 40 = 100

6x + 88 = 100

6x = 1

2 x = 2

D, 15x - 133 = 17

15x = 150

x = 10

E, 90[x + 2] = 45

90x + 180 = 45

90x = -135

x = -1.5

F, 4x + 54 = 82

4x = 28

x = 7

G, 17x - 20 = 14

17x = 34

x = 2

Nếu bạn muốn có lời giải thì ít thôi @.@

Katherine Lilly Filbert nói rất đúng câu hỏi nhiều như vậy ai mà trả lời đc hết cơ chứ

2x^2-3x-5=(x+1)(2x-5) => 2x^2-3x-5 co 2 nghiem x=-1 va x=5/2

x^3+4x^2+x-6=(x-1)(x+2)(x+3) =>x^3+4x^2+x-6 co 3 nghiemx=1;x=-2 va x=-3

36x^4+12x^3-17x^2-3x+2=(2x-1)^2(3x-1)(3x+2) => 36x^4+12x^3-17x^2-3x+2 co 3 nghiem x=1/2;x=1/3 va x=-2/3

a,\(2x^2-3x-5\)

=\(2\left(x^2-2x.\frac{3}{4}+\frac{9}{16}\right)-\frac{49}{8}\)

=\(2\left(x-\frac{3}{4}\right)^2-\frac{49}{8}\)

Để g(x) có nghiệm

=>\(2\left(x-\frac{3}{4}\right)^2-\frac{49}{8}\)=0

=>\(2\left(x-\frac{3}{4}\right)^2=\frac{49}{8}\)

=>\(\left(x-\frac{3}{4}\right)^2=\frac{49}{16}\)

=>x=-1 hoặc x=5/2

Vậy x=-1 hoặc x=5/2