\(a,=30x^3-6x^2-12x\\ b,=-6x^5-2x^3+x^2\)

cảm ơn bạn nhé

a) Ta có: B(x)-M(x)=A(x)

nên M(x)=B(x)-A(x)

\(=x^4-2x^3+5x^2+x+10-x^4-2x^3+5x^2+3x+6\)

\(=-4x^3+10x^2+4x+16\)

`a)`

`Q(x)=-2x^{3}+7x^{2}-9x+12`

`b)`

`P(x)+Q(x)=4x^{3}-7x^{2}+3x-12-2x^{3}+7x^{2}-9x+12`

`=2x^{3}-6x`

``

`2P(x)-Q(x)=8x^{3}-14x^{2}+6x-24-2x^{3}+7x^{2}-9x+12`

`=6x^{3}-7x^{2}-3x-12`

`c)`

`P(x)+Q(x)=0`

`->2x^{3}-6x=0`

`->2x(x^{2}-3)=0`

`->x=0` hoặc `x^{2}-3=0`

`->x=0` hoặc `x=+-\sqrt{3}`

a) \(Q=-2x^3+2x^2+12+5x^2-9x=-2x^3+7x^2-9x+12\)

b) \(P+Q=4x^3-7x^2+3x-12-2x^3+7x^2-9x+12=2x^3-6x\)

\(2P-Q=2\left(4x^3-7x^2+3x-12\right)-\left(-2x^3+7x^2-9x+12\right)=8x^3-14x^2+6x-24+2x^3-7x^2+9x-12=10x^3-21x^2+15x-36\)c) \(P+Q=2x^3-6x=0\)

\(\Leftrightarrow2x\left(x^2-3\right)=0\Leftrightarrow\left[{}\begin{matrix}2x=0\\x^2-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\pm\sqrt{3}\end{matrix}\right.\)

C2: (2x - 3)³ + (6x - 17)³

= (2x - 3 + 6x - 17)\(\left[\left(2x-3\right)^2-\left(2x-3\right)\left(6x-17\right)+\left(6x-17\right)^2\right]\)

= (8x - 20)(4x² - 12x + 9 - 12x² + 34x + 18x - 51 + 36x² - 204x + 289)

= (8x - 20)(4x² - 12x² + 36x² - 12x + 34x + 18x - 204x + 9 - 51 + 289)

= (8x - 20)(28x² - 164x + 247)

Câu 1: 

Ta có: \(3x^3-5x-2\)

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

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

1: \(=x^2+1\)

3: \(=\left(x-y-z\right)^2\)

ai giúp dii

\(\Leftrightarrow\left(x+1\right)^3=0\Leftrightarrow x+1=0\Leftrightarrow x=-1\)

<=>x³ +3x²1 +3x1²+1²=0

<=>(x+1)²=0

<=>x+1=0

<=>x=-1

\(b,7+3x=3\)

\(\Leftrightarrow3x=-4\)

\(\Leftrightarrow x=-\dfrac{4}{3}\)

\(c,6y+2=20\)

\(\Leftrightarrow6y=18\)

\(\Leftrightarrow y=3\)

\(d,4y=10\)

\(\Leftrightarrow y=\dfrac{10}{4}\)

\(\Leftrightarrow y=\dfrac{5}{2}\)

\(e,5x-7=13\)

\(\Leftrightarrow5x=20\)

\(\Leftrightarrow x=4\)

\(f,\dfrac{4}{3}x+\dfrac{7}{2}=10\)

\(\Leftrightarrow\dfrac{4}{3}x=\dfrac{13}{2}\)

\(\Leftrightarrow x=\dfrac{39}{8}\)

\(g,4-\dfrac{2}{3}y=2\)

\(\Leftrightarrow\dfrac{2}{3}y=2\)

\(\Leftrightarrow y=3\)

\(h,6x=36\Leftrightarrow x=6\)

\(j,7x-3=0\)

\(\Leftrightarrow7x=3\)

\(\Leftrightarrow x=\dfrac{3}{7}\)