a) \(\left(x-2\right).\left(2x-1\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-2=0\\2x-1=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\2x=1\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\x=\frac{1}{2}\end{cases}}\)

b) \(\left(3x+9\right).\left(1-3x\right)=0\)

\(\Rightarrow\orbr{\begin{cases}3x+9=0\\1-3x=0\end{cases}}\Rightarrow\orbr{\begin{cases}3x=-9\\3x=1\end{cases}\Rightarrow}\orbr{\begin{cases}x=-3\\x=\frac{1}{3}\end{cases}}\)

c) (31 - 2x)³ =27

    (31 - 2x)³ = 3³

=> 31 - 2x = 3

            2x = 31 - 3 

           2x = 28

             x = 14

a. \(\left(x-2\right).\left(2x-1\right)=0\Leftrightarrow\orbr{\begin{cases}x-2=0\\2x-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=\frac{1}{2}\end{cases}}}\)

Vậy \(x=2\)hoặc \(x=\frac{1}{2}\)

b.\(\left(3x+9\right).\left(1-3x\right)=0\Leftrightarrow\orbr{\begin{cases}3x+9=0\\1-3x=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-3\\x=\frac{1}{3}\end{cases}}}\)

Vậy \(x=-3\)hoặc \(x=\frac{1}{3}\)

c.\(\left(31-2x\right)^3=-27\)

\(\Leftrightarrow\left(31-2x\right)^3=\left(-3\right)^3\)

\(\Leftrightarrow31-2x=-3\)

\(2x=34\)

\(x=17\)

d.\(\left(x-2\right).\left(7-x\right)=0\Leftrightarrow\orbr{\begin{cases}x-2=0\\7-x=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=7\end{cases}}}\)

Vậy \(x=2\)hoặc \(x=7\)

e.\(\left(x-5\right)^5=32\)

\(\Leftrightarrow\left(x-5\right)^5=2^5\)

\(\Leftrightarrow x-5=2\Leftrightarrow x=7\)

f.\(\left(2-x\right)^4=81\)

\(\Leftrightarrow\left(2-x\right)^4=3^4\)

\(2-x=3\Leftrightarrow x=-1\)

g.\(\left|x-7\right|< 3\Leftrightarrow-3< x-7< 3\Leftrightarrow4< x< 10\)

-(127+38-21)-(121-27+48)+50

=-127-38+21-121+27-48+50

=(-127+27)-(38+48)+(21-121)+50

=-100-86-100+50

=-(100+100+86)+50

=-286+50

=-236

-39+(193-127+96)-(193+196-127)

=-39+193-127+96-193-196+127

=-39+(193-193)-(127+127)+(96-196)

=-39-100

=-139

a: =>|x-2|-9=-8

=>|x-2|=1

=>x-2=1 hoặc x-2=-1

=>x=1 hoặc x=3

b: =>3|x-1|=27

=>|x-1|=9

=>x-1=9 hoặc x-1=-9

=>x=-8 hoặc x=10

c:=>3|2x-3|=21

=>|2x-3|=7

=>2x-3=7 hoặc 2x-3=-7

=>x=5 hoặc x=-2

d: =>2x=-12

=>x=-6

e: =>2|x-5|=2

=>|x-5|=1

=>x-5=1 hoặc x-5=-1

=>x=4 hoặc x=6

a,6³¹=6³¹

b, 27¹⁶:9¹⁰=(3³)¹⁶:(3²)¹⁰=3⁴⁸:3²⁰=3²⁸

c,(1+2+3+.....+100).(1²+2²+3²+...+10²).(65.111-13.15.17)

=(1+2+3+.....+100).(1²+2²+3²+...+10²).(13.15.17-13.15.17)

=(1+2+3+.....+100).(1²+2²+3²+...+10²).0

=0

nhớ like

\(2^x=2\Rightarrow x=1\)

\(2^{2x+2}=8^2\Rightarrow2^{2x+2}=2^6\Rightarrow2x+2=6\)\(2x=6-2=3\Rightarrow x=3:2=\frac{3}{2}\)

suy ra 0^27=0^127 hoặc 1^27 =1^127

nếu x-3=0 thi x =3

x-3=1thì x=4

Vậy x=3;4