![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
-->415-9x-18=800
-->415-9x=800-18=782
-->415-782=9x
-->-367=9x
-->x=-367:9=-367/9
-->x=-367/9
____________________
li-ke cho mk nha bn
![](https://rs.olm.vn/images/avt/0.png?1311)
-45 x 65 - 45 x 30 - 45 x 3
= -45 x (65 + 30 + 3)
= -45 x 98
= -230
a) -5x (-9) = -11\(\Rightarrow-5\chi=\frac{11}{9}\Rightarrow\chi=\frac{11}{9}:\left(-5\right)\Rightarrow\chi=\frac{11}{9}.\frac{-1}{5}\Rightarrow\chi=\frac{-11}{45}\)b) 25 - (x + 5 ) = -415 - ( 15-415)\(\Rightarrow25-\left(\chi+5\right)=-415-15+415\)
\(\Rightarrow25-\left(\chi+5\right)=\left(-415+415\right)-15\)
\(\Rightarrow25-\left(\chi+5\right)=-15\Rightarrow\chi+5=25+15\)
\(\Rightarrow\chi+5=40\Rightarrow\chi=35\)
HTDT
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{1}{5}:\dfrac{1}{10}-\dfrac{1}{3}\left(\dfrac{6}{5}-\dfrac{9}{4}\right).\\ =2-\dfrac{1}{3}.\dfrac{-21}{20}.\\ =2-\left(-\dfrac{7}{20}\right)=2+\dfrac{7}{20}=\dfrac{47}{20}.\)
\(31,2.1,8-315,4:415.\\ =56,16-0,76=55,4.\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(x-36\right):18=3\Leftrightarrow x-36=54\Leftrightarrow x=90\)
\(415-9\left(x+2\right)=2^2.5^2\Leftrightarrow415-9\left(x+2\right)=100\Leftrightarrow9\left(x+2\right)=315\Leftrightarrow x+2=35\Leftrightarrow x=33\)
\(5\left(4+6x\right)=290\Leftrightarrow4+6x=58\Leftrightarrow6x=54\Leftrightarrow x=9\)
Bài làm :
\(\left(x-36\right)\div18=3\)
\(\Leftrightarrow x-36=3\times18\)
\(\Leftrightarrow x-36=54\)
\(\Leftrightarrow x=54+36=90\)
\(415-9\times\left(x+2\right)=2^2\times5^2\)
\(\Leftrightarrow415-9\times x-9\times2=\left(2\times5\right)^2\)
\(\Leftrightarrow415-9\times x-18=10^2\)
\(\Leftrightarrow397-9\times x=100\)
\(\Leftrightarrow9\times x=397-100\)
\(\Leftrightarrow9\times x=297\)
\(\Leftrightarrow x=297\div9=33\).
\(5\times\left(4+6\times x\right)=290\)
\(\Leftrightarrow4+6\times x=290\div5\)
\(\Leftrightarrow4+6\times x=58\)
\(\Leftrightarrow6\times x=58-4\)
\(\Leftrightarrow6\times x=54\)
\(\Leftrightarrow x=54\div6=9\)
Chúc bạn học tốt !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
![](https://rs.olm.vn/images/avt/0.png?1311)
1. 3x - 17 = x+3
3x - x = 3 + 17
2x = 20
x = 20 :2
x = 10
2. |x-3| - 12 = |-5|
|x-3| -12 = 5
|x-3| = 5 + 12
|x-3| = 17
=> x-3 = +17 , -17
- x - 3 = 17
x = 17 + 3
x = 20
- x - 3 = -17
x = -17 + 3
x = -14
3 . 25 - ( x -5 ) = -415 -( 15 -415)
25 - x +5 = -415 - 15 +415
25 - x +5 = ( -415 + 415) -15
25 - x +5 = 0-5 = -5
25 - x = -5-5
25 - x = -10
x = 25 - -10
x = 35
4. ( x -3 ) . ( 2x +6 ) = 0
=> x-3 = 0 hoặc 2x +6 = 0
- x - 3 = 0
x = 0 + 3 = 3
- 2x +6 = 0
2x = 0-6=-6
x = -6 : 2
x = -3
\(1;3x-17=x+3\)
\(\Leftrightarrow3x-x=3+17\)
\(\Leftrightarrow2x=20\)
\(\Rightarrow x=10\)
\(2;\left|x-3\right|-12=\left|-5\right|\)
\(\Leftrightarrow\left|x-3\right|-12=5\)
\(\Leftrightarrow\left|x-3\right|=5+12\)
\(\Leftrightarrow\left|x-3\right|=17\)
\(\Rightarrow\orbr{\begin{cases}x-3=17\\3-x=17\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=17+3\\-x=17-3\end{cases}\Leftrightarrow\orbr{\begin{cases}x=20\\x=-14\end{cases}}}\)
\(3;25-\left(x-5\right)=-415-\left(15-415\right)\)
\(\Leftrightarrow25-x+5=-415-15+415\)
\(\Leftrightarrow-x=-415-15+415-25-5\)
\(\Leftrightarrow-x=-45\)
\(\Rightarrow x=45\)
\(4;\left(x-3\right)\left(2x+6\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\2x+6=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\\x=-3\end{cases}}}\)
415 - 9(x - 2) = 100
415 - 9x + 18 = 100
433 - 9x = 100
9x = 433 - 100
9x = 333
x = 333 : 9
x = 37
ai kết bạn đi