A. x=0 hay x=3

B. x=2

C. x=0 hay x=9

Giải ra nha bn

`(3/4+x) xx 1/2=4/5`

`3/4+x=4/5:1/2`

`3/4+x=4/5 . 2`

`3/4+x=8/5`

`x=8/5 - 3/4`

`x = 24/20 - 15/20`

`x=17/20`

\(\left(\dfrac{3}{4}+x\right)\times\dfrac{1}{2}=\dfrac{4}{5}\)

`=>3/4+x=4/5:1/2`

`=>3/4+x=2/5`

`=>x=2/5-3/4`

`=>x=-7/20`

a có : x50 = x

=> x⁵⁰ - x = 0

=> x.(x⁴⁹-1)=0

\(\Rightarrow\left[{}\begin{matrix}x=0\\x^{49}-1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x^{49}=1\end{matrix}\right.\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)

`x^50 = x`

`x^50 -x=0`

`x.(x^49-1)=0`

`=>`\(\left[{}\begin{matrix}x=0\\x^{49}-1=0\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=0\\x^{49}=0+1=1\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=0\\x^{49}=1^{49}\Rightarrow x=1\end{matrix}\right.\)

Vậy `x = {0;1}`

`136-3.(2x-9)=115`

`3.(2x-9)=136-115`

`3.(2x-9)= 21`

`2x-9=21:3`

`2x-9=7`

`2x=7+9`

`2x=16`

`x=16:2`

`x=8`

_______________________________________

`5,6 : x - 50% = 0,25`

`5,6 :x - 0,5 = 0,25`

`5,6 : x = 0,25 + 0,5`

`5,6:x = 0,75`

`x = 5,6 : 0,75`

`x=112/15`

_______________________________________________

`(x+1)+(2x+3)+(4.8x) = 110`

`x+1 +2x+3+4.8x = 110`

`x+1+2x+3+24x=110`

`(x+2x+24x) +(1+3)= 110`

`27x +4 = 110`

`27x = 110-4`

`27x=106`

`x=106:27`

`x=106/27`

_______________________________________

`3/8 -1/8:x=1/2`

`1/8:x=3/8-1/2`

`1/8:x=3/8 - 4/8`

`1/8:x = -1/8`

`x=1/8:(-1)/8`

`x=1/8 . (-8)`

`x=-1`

`a) 851 + 486 - 751 - 186`

`=(851 - 751) + (486 - 186)`

`=100+ 300`

`=400`

`b) 0,3607 : 0,01 + 36 , 07 x 95 + 36,07 : 0, 65`

`=0,3607 xx 100 + 36,07 xx 95 + 36,07 :0,65`

`=36,07 xx 100 + 36,07 xx 95 + 36,07 :0,65`

`=36,07 xx (100 + 95 : 0,65)`

`=3518.21230769`

`=>` Đề sai

`c) 0,2 xx 317 xx 7 + 0,14 xx 3520 + 33,1 xx 14`

`=(0,2 xx 7) xx 317 + 0,14 xx 3520 + 33,1 xx 14`

`=1,4 xx 317 + 0,14 xx 3520 + 33,1 xx 14`

`=1,4 xx 317 + 0,14 xx 3520 + 331 xx 1,4`

`=1,4 xx 317 + 1,4 xx 352 + 331 xx 1,4`

`= 1,4 xx (317 + 352 + 331)`

`=1,4 xx 1000`

`=1400`

a) 4x - 15 + x = 75

           4x + x = 75 + 15

                 5x = 90

                   x = 90 : 5

                   x = 18

b) (x - 6).(2x - 6) = 0

⇒\(\left[{}\begin{matrix}x-6=0\\2x-6=0\end{matrix}\right.\)

⇒\(\left[{}\begin{matrix}x=0+6\\2x=0+6\end{matrix}\right.\)

⇒\(\left[{}\begin{matrix}x=6\\2x=6\end{matrix}\right.\)

⇒\(\left[{}\begin{matrix}x=6\\x=6:2\end{matrix}\right.\)

⇒\(\left[{}\begin{matrix}x=6\\x=3\end{matrix}\right.\)

`4x-15+x=75`

`(4x+x)-15=75`

`5x-15=75`

`5x=75+15`

`5x=90`

`x=90:5`

`x=18`

_______________________________

`(x-6).(2x-6)=0`

`@Th1:`

`x-6=0`

`x=0+6`

`x=6`

`@Th2:`

`2x-6=0`

`2x=0+6`

`2x=6`

`x=6:2`

`x=3`

Vậy `x = {6;3}`

   16² : 64 + 18⁹ : 18⁷ - 3⁴.1⁹

= (4²)² : 4³ + 18² - 3⁴.1

= 4⁴ : 4³ + 9².2² - 3⁴

= 4 + 81.4 - 81

= 4 + 324 - 81 

= 328 - 81

= 247

\(2018^{2019}-2018^{2018}=2018^{2018}\left(2018-1\right)=2017.2018^{2018}\)

\(2018^{2018}-2018^{2017}=2018^{2017}\left(2018-1\right)=2017.2018^{2017}\)

\(\Rightarrow2017.2018^{2018}>2017.2018^{2017}\)

\(\Rightarrow2018^{2019}-2018^{2018}>2018^{2018}-2018^{2017}\)