\(x\times0,49+x\times0,01=1,2\\ =>x\times\left(0,49+0,01\right)=1,2\\ =>x\times0,5=1,2\\ =>x=1,2:0,5\\ =>x=2,4\)

X x 0,49 + X x 0,01 = 1,2 

X x (0,49 + 0,01) = 1,2 

X x 0,5 = 1,2 

X = 1,2 : 0,5 

X = 2,4 

h

\(1,35-x+0,49=0,48\)

\(0,86-x=0,48\)

\(x=0,38\)

\(1,35-x+0,49=0,48\)

\(x-0,49=1,35-0,48\)

\(x-0,49=0,87\)

\(x=0,87+0,49\)

\(x=1,36\)

Vậy x = 1,36

x² (x - y) = 5 (y - 1)

=> x² (x - y) (y - 1) = 5

=> x² .xy - x - y - y = 5

=> x² (xy - x) - 2y = 5

=> x² - x(y + 1) - 2y = 5

=> (x² - x) (y + 1) - 2y = 5

=> x(x - 1)(y + 1) - 2y = 5

=> (x - 1) (y + 1) (x - 2y) = 5

=> \(\hept{\begin{cases}x-1=5\\y+1=5\\x-2y=5\end{cases}}\)

bó tay1!!!!!!!!!!!!5645775687697897894525256346436546457567567576876887956867876

sai nha mk k nhầm

X x 1,2 + X x 1,8 = 1,35

X x ( 1,2 + 1,8 )  = 1,35

            X x 3     = 1,35

                  X    = 1,35 : 3

                  X    = 0,45

Vậy x = 0,45 

X nhân(1,2+1,8)=1,35

X nhân3=1,35

X=1,35:3

X=0,45

\(\frac{4,95}{x}=\frac{1,35}{x}+1,2\)

\(\Rightarrow\frac{99}{20x}=\frac{27}{20x}+\frac{6}{5}\)

\(\Rightarrow\frac{99}{20x}-\frac{27}{20x}=\frac{6}{5}\)

\(\Rightarrow\frac{72}{20x}=\frac{6}{5}\)

\(\Rightarrow\frac{18}{5x}=\frac{6}{5}\)

\(\Rightarrow x=\frac{18}{6}=3\)

Vậy x = 3 

làm ik ai đúng mk k

x = 3 nhé

dễ thấy vế trái luôn>0 nên 6x>0=> x>0

x>0, bỏ dấu trị tuyệt đối ra ta đc 4x+10=6x

x=5

chúc bạn học giỏi, ăn Tết đc ngon, hehe -_-

HYC-30/1/2022

Answer:

\(\left|x+1\right|+\left|x+2\right|+\left|x+3\right|+\left|x+4\right|=6x\)

Có \(\left|x+1\right|+\left|x+2\right|+\left|x+3\right|+\left|x+4\right|\ge0\)

\(\Rightarrow6x\ge0\)

\(\Rightarrow x\ge0\)

\(\Rightarrow x+1+x+2+x+3+x+4=6x\)

\(\Rightarrow4x+10=6x\)

\(\Rightarrow2x=10\)

\(\Rightarrow x=5\)

1) \(5-\left(1+\dfrac{1}{3}\right):\left(1-\dfrac{1}{3}\right)\)

\(=5-\dfrac{4}{3}:\dfrac{2}{3}\)

\(=5-\dfrac{4}{3}\cdot\dfrac{3}{2}\)

\(=5-\dfrac{4}{2}\)

\(=5-2\)

\(=3\)

b) \(\left(1+\dfrac{2}{3}-\dfrac{5}{4}\right)-\left(1-\dfrac{5}{4}\right)+2022-\dfrac{2}{3}\)

\(=1+\dfrac{2}{3}-\dfrac{5}{4}-1+\dfrac{5}{4}++2022-\dfrac{2}{3}\)

\(=\left(1-1\right)+\left(\dfrac{2}{3}-\dfrac{2}{3}\right)+\left(-\dfrac{5}{4}+\dfrac{5}{4}\right)+2022\)

\(=0+0+0+2022\)

\(=2022\)

2) \(0,7^2\cdot x=0,49^2\)

\(\Rightarrow x=\dfrac{0,49^2}{0,7^2}\)

\(\Rightarrow x=\left(\dfrac{0,49}{0,7}\right)^2\)

\(\Rightarrow x=\left(0,7\right)^2\)

\(\Rightarrow x=0,49\)

b) \(x:\left(-0,5\right)^3=\left(0,5\right)^2\)

\(\Rightarrow x=\left(0,5\right)^2\cdot\left(-0,5\right)^3\)

\(\Rightarrow x=\left(-0,5\right)^5\)

\(\Rightarrow x=-\dfrac{1}{32}\)

2:

a: =>x*0,49=0,49^2

=>x=0,49

b: =>x=(0,5)^2*(-1)*(0,5)^3=-(0,5)^5

b. \(\dfrac{13+x}{20}\)= \(\dfrac{15}{20}\)

=>  13+x=15

            x=15-13

            x=2

$#Shả$

`x xx1,2+x xx1,8=45`

`<=>x xx(1,2+1,8)=45`

`<=> x xx 3 =45`

`<=>x=45:3=15`

`(13+x)/20=3/4`

`<=>4xx(13+x)=20xx3`

`<=>4xx(13+x)=60`

`<=>13+x=60:4=15`

`<=>x=15-13=2`

a. x x(1,2+1,8)=45

    x x 3= 45

    x= 45:3

    x=15