a) \(\left(x+1\right)^3-\left(x-1\right)^3-6\cdot\left(x-1\right)^2=10\)

\(\Rightarrow x^3+3x^2+3x+1-x^3+3x^2-3x+1-6\cdot\left(x^2-2x+1\right)=10\)

\(\Rightarrow6x^2+2-6x^2+12x-6=10\)

\(\Rightarrow12x-4=10\)

\(\Rightarrow12x=14\)

\(\Rightarrow x=\dfrac{7}{6}\)

b) \(x\left(x+5\right)\left(x-5\right)-\left(x+2\right)\left(x^2-2x+4\right)=42\)

\(\Rightarrow x\left(x^2-25\right)-\left(x^3+8\right)=42\)

\(\Rightarrow x^3-25x-x^3-8=42\)

\(\Rightarrow-25x-8=42\)

\(\Rightarrow-25x=50\)

\(\Rightarrow x=\dfrac{50}{-25}=-2\)

c) \(\left(x-2\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2=49\)

\(\Rightarrow x^3-6x^2+12x-8-\left(x^3-27\right)+6\left(x^2+2x+1\right)=49\)

\(\Rightarrow x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=49\)

\(\Rightarrow24x+25=49\)

\(\Rightarrow24x=24\)

\(\Rightarrow x=\dfrac{24}{24}=1\)

a) `3(2-x)+5(x-6)=-98`

`6-3x+5x-30=-98`

`-3x+5x=-98-6+30`

`2x=-74`

`x=-37`

b) `(x+7)(8-x)=0`

\(\left[{}\begin{matrix}x+7=0\\8-x=0\end{matrix}\right.\\ \left[{}\begin{matrix}x=-7\\x=8\end{matrix}\right.\)

a, \(3\left(2-x\right)+5\left(x-6\right)=-98\)

\(6-3x+5x-30=-98\)

\(2x-24=-98\)

\(2x=-74\)

\(x=-37\)

b,\(\left(x+7\right)\left(8-x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-7\\x=8\end{matrix}\right.\)

-Chúc bạn học tốt-

Giải:

a) \(3.\left(2-x\right)+5.\left(x-6\right)=-98\) 

           \(6-3x+5x-30=-98\) 

                       \(-3x+5x=-98-6+30\) 

                                  \(2x=-74\) 

                                    \(x=-74:2\) 

                                    \(x=-37\) 

b) \(\left(x+7\right).\left(8-x\right)=0\) 

\(\Rightarrow\left[{}\begin{matrix}x+7=0\\8-x=0\end{matrix}\right.\) 

\(\Rightarrow\left[{}\begin{matrix}x=-7\\x=8\end{matrix}\right.\) 

Chúc bạn học tốt!

a: x=5:(-1/2)=-10

b: x=8/3+1/9=25/9

c: =>x+5/6=11/21

=>x=-13/42

d: =>7/4x-5=-10/3

=>7/4x=5/3

=>x=20/21

e: =>10/3-3/4:x=-1/6

=>3/4:x=10/3+1/6=21/6=7/2

=>x=3/4:7/2=3/4*2/7=6/28=3/14

g: =>3/(x+5)=3/20

=>x+5=20

=>x=15

h: =>1-1/2+1/2-1/3+...+1/x-1/x+1=49/50

=>1-1/x+1=49/50

=>x+1=50

=>x=49

1: =>(x+3)(x-5)=0

=>x=5 hoặc x=-3

2: =>(x-1)(5x-1)=0

=>x=1/5 hoặc x=1

5: =>(x-4)*x=0

=>x=0 hoặc x=4

10: =>(x+5)(x-3)=0

=>x=3 hoặc x=-5

9: =>(x-2)(x-4)=0

=>x=2 hoặc x=4

7: =>(x-6)(2x-1)=0

=>x=1/2 hoặc x=6

8: =>(2x-1)(3x-12)=0

=>x=4 hoặc x=1/2

a: Ta có: \(\left(x+2\right)\left(x+3\right)-\left(x-2\right)\left(x+5\right)=6\)

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

\(\Leftrightarrow2x=-10\)

hay x=-5

b: Ta có: \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)

\(\Leftrightarrow6x^2+27x+4x+18-6x^2-x-12x-2=x+1-x+6\)

\(\Leftrightarrow18x+16=7\)

hay \(x=-\dfrac{1}{2}\)

c: Ta có: \(3\left(2x-1\right)\left(3x-1\right)-\left(2x-3\right)\left(9x-1\right)=0\)

\(\Leftrightarrow3\left(6x^2-2x-3x+1\right)-\left(18x^2-2x-27x+3\right)=0\)

\(\Leftrightarrow18x^2-15x+3-18x^2+27x-3=0\)

hay x=0

a. 5 - 3(x + 4) = -1

⇔ 5 - 3x - 12 = -1

⇔ 3x = -1 - 5 + 12

⇔ 3x = 6

⇔ x = 2

\(d,2x^2-3=5\)

\(\Leftrightarrow2x^2=8\)

\(\Leftrightarrow x^2=4\)

\(\Leftrightarrow x=\pm2\)

\(e,x\left(2x-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-1=0\\x=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}2x=1\\x=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=0\end{matrix}\right.\)

a)\(=>3\left(x+4\right)=6=>x+4=2=>x=-2\)

b)\(=>x-1-x-2=0\)

\(=>-3=0\left(vl\right)\) => x ko tồn tại