\(1,\Rightarrow3^{x-3}=\left(3^2\right)^8:\left(3^3\right)^5=3^{16}:3^{15}=3^1\\ \Rightarrow x-3=1\\ \Rightarrow x=4\\ 2,\Rightarrow7^x\left(1+7^2\right)=350\\ \Rightarrow7^x=\dfrac{350}{50}=7=7^1\\ \Rightarrow x=1\)

\(3,\Rightarrow2^{2+2x+2}-2^{2x}=240\\ \Rightarrow2^{2x}\left(2^4-1\right)=240\\ \Rightarrow2^{2x}=\dfrac{240}{15}=16=2^4\\ \Rightarrow2x=4\Rightarrow x=2\)

a) 125 x 25 x 64

= ( 25 x 64 ) x 125

= 1600 x 125 

= 200 000

b) 125 x 25 x 12 x 14

=  ( 125 x 12 ) x ( 25 x 14 )

= 1500 x 350

= 525000

c) 1300 : 50 = 26

d) 700 : 25 = 28

a, = 125 x (25x64)=125 x 1600= 200 000

b, = (125 x 24) x ( 25 x 12) = 3000 x 300 = 900 000

c, 1300 : 50 = 26

d, 700 : 25 = 28.

a) \(\left(-4\right).125.\left(-25\right).\left(-6\right).\left(-8\right)\)

\(=\left(-4\right)\left(-25\right)\left(-8\right).125.\left(-6\right)\)

\(=100.\left(-1000\right).\left(-6\right)\)

\(=600000\)

b) \(\left(-98\right)\left(1-246\right)-246.98\)

\(=\left(-98\right)\left(-245\right)-246.98\)

\(=98.245-246.98\)

\(=98.\left(245-246\right)=98.\left(-1\right)=-98\)

a, (-4 ) * [(+125)

a)(-4).(-3).(-125).25.(-8)

=[(-4).25].[(-125).(-8)].3

=(-100).1000.3

=-100000.3

=-300000

b)(-4).9.(-125).25.(-8)

=[(-4).25].[(-8).(-125)].9

=(-100).1000.9

=-100000.9

=-900000

a)524.[23+(-45)] + 524.(-45+123)

=524.(-22) + 524.78

=524.(-22+78)

=524.100

=52400

a) = (8 x 125) x7

    = 1000 x 7 

    = 7000

a) 8 x 7 x 125 = 125 x 8 x 7

                       = 1000 x 7 = 7000

b) 125 x 1008 = 125 x 1000 x 8

                       = 125000 x 8

                       = 1000000

Chúc bạn học tốt!

Thân!

8+(x-9) = 8+x-9 = 125-64

  =>      8+x       = 70

  =>          x       = 70 - 8

  =>          x        = 62

 Vậy x = 62

bt lm r thì đừng hỏi!