a/3^x(3²-1)=72

3^x.8=72

3^x=9

3^x=3²

x=2

{8.30-[76-(9-3)² ]} :50

={240-[76-36]} :50

={240-40} :50

=200:50 =4
 

8.30-{[76 - 36]} : 50

8. -10 : 50 = -0,032

Ha Giang giai dung rồi
 

=(240-(76-6²)):50

=(240-40):50

=200:50

=4

nhầm 

{2³-[76-(9-3)²]} : 50

= 2³ - [76 - 36] : 50

= 8 - 40 : 50

= 8 - 4/5

= 36/5

\(\left\{2^2.30-\left[76-\left(9-3\right)^2\right]\right\}:50\)

\(=\left[2^2.30-\left(76-6^2\right)\right]:50\)

\(=\left[2^2.30-\left(76-36\right)\right]:50\)

\(=\left(2^2.30-40\right):50\)

\(=\left(4.30-40\right):50\)

\(=\left(120-40\right):50\)

\(=80:50\)

\(=\dfrac{8}{5}\)

\(=1,6\)

\(\left\{2^3.30-\left[76-\left(9-3\right)^2\right]\right\}:50\)

\(=\left\{8.30-\left[76-6^2\right]\right\}:50\)

\(=\left\{240-\left[76-36\right]\right\}:50\)

\(=\left\{240-40\right\}:50\)

\(=200:50\)

\(=4\)

{2³.30-[76-(9-3)²]}:50

={ 8 . 30 - [ 76 - 6² ] } : 50

={ 240 - [ 76 - 36 ] } : 50

= { 240 - 40 } : 50

= 200 : 50

= 4

\(243-4x=3^9\div3^6\)

\(243-4x=3^3\)

\(243-4x=27\)

\(4x=243-27\)

\(4x=216\)

\(x=216\div4\)

\(x=54\)

\(5^x\div5^2=125\)

\(5^{x-2}=5^3\)

\(\Rightarrow x-2=3\)

\(\Leftrightarrow x=5\)

\(\left(x-30\right)\div2-150=10\)

\(\left(x-30\right)\div2=160\)

\(x-30=320\)

\(x=290\)

(x+2)+(x+4)+...+(x+1996) = 99800

=> (x+x+x+...+x)+(2+4+...+1996) = 99800

=> 998x + 997002 = 99800

998x = 99800 - 997002

998x = -897202

x = -897202 : 998

x = -899