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a) \(2.\left|5x-3\right|-2x=14\)
\(2\left|5x-3\right|=14+2x\)
\(\left|5x-3\right|=\frac{14+2x}{2}\)
\(\Rightarrow\orbr{\begin{cases}5x-3=\frac{-14-2x}{2}\\5x-3=\frac{14+2x}{2}\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}\left(5x-3\right).2=-14-2x\\\left(5x-3\right).2=14+2x\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}10x-6+2x=-14\\10x-6-2x=14\end{cases}\Rightarrow\orbr{\begin{cases}12x=-14+6\\8x=14+6\end{cases}}}\Rightarrow\orbr{\begin{cases}12x=-8\\8x=20\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{-2}{3}\\x=2,5\end{cases}}\)
vậy \(\orbr{\begin{cases}x=\frac{-2}{3}\\x=2,5\end{cases}}\)
Những câu sau tương tự nhé.
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a) \(M(x) = A(x) + B(x) \\= 4{x^4} + 6{x^2} - 7{x^3} - 5x - 6 - 5{x^2} + 7{x^3} + 5x + 4 - 4{x^4} \\=(4x^4-4x^4)+(-7x^3+7x^3)+(6x^2-5x^2)+(-5x+5x)+(-6+4)\\= {x^2} - 2.\)
b) \(A(x) = B(x) + C(x) \Rightarrow C(x) = A(x) - B(x)\)
\(\begin{array}{l}C(x) = A(x) - B(x)\\ = 4{x^4} + 6{x^2} - 7{x^3} - 5x - 6 - ( - 5{x^2} + 7{x^3} + 5x + 4 - 4{x^4})\\ = 4{x^4} + 6{x^2} - 7{x^3} - 5x - 6 + 5{x^2} - 7{x^3} - 5x - 4 + 4{x^4}\\ =(4x^4+4x^4)+(-7x^3-7x^3)+(6x^2+5x^2)+(-5x-5x)+(-6-4)\\= 8{x^4} - 14{x^3} + 11{x^2} - 10x - 10\end{array}\)
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a) 3/35 - (3/5 + x) = 2/7
=> 3/5 + x= 3/35- 2/7
=> 3/5 +x = -1/5
=> x = -1/5 -3/5
=> x = -4/5
b) 3/7 +1/7 : x = 3/14
=> 1/7 : x= 3/14 -3/7
=> 1/7 : x = -3/14
=> x = 1/7 : -3/14
=> x = -2/3
c) (5x-1).(2x-1/3)=0
=> \(\left[{}\begin{matrix}5x-1=0\\2x-\dfrac{1}{3}=0\end{matrix}\right.\)
=> \(\left[{}\begin{matrix}5x=0+1=1\\2x=0+\dfrac{1}{3}=\dfrac{1}{3}\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=\dfrac{1}{5}\\x=\dfrac{1}{3}:2=\dfrac{1}{6}\end{matrix}\right.\)
Học tốt :D
a)x=-4/5
b)x=-2/3
c)\(\left\{{}\begin{matrix}5x-1=0\\2x-\dfrac{1}{3}=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}5x=1\\2x=\dfrac{1}{3}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{1}{5}\\x=\dfrac{1}{6}\end{matrix}\right.\)
Vậy.........
mik lười mong bn thông cảm
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left(5x+3\right)-x=7\)
\(\Leftrightarrow5x+3-x=7\)
\(\Leftrightarrow4x=4\)
\(\Leftrightarrow x=1\)
Vậy x=1
Học tốt
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TH1: x<3/5 suy ra 5x-3<0 suy ra|5x-3|=3-5x
ta có: 3-5x-x=7
-6x=4
x=-2/3(loại)
TH2:x>/3/5 suy ra 5x-3>/0 suy ra |5x-3|=5x-3
ta có: 5x-3-x=7
4x=10
x=5/2(chọn)
vậy x=5/2
Trường Hợp 1: 5x-3>0 =>x>3/5
=>5x-3-x=7
=>5x-x=7+3
=>4x=10 =>x=5/2 (thỏa mãn)
Trường Hợp 2:
5x-3<0 =>x<3/5
=>-(5x-3)-x=7 =>-5x+3-x=7 =>-5x-x=7-3
-6x=4 =>x=-2/3(thỏa mãn)
Vậy: x đạt hai giá trị: x=5/2 (với x>3/5)
x=-2/3(với x<3/5)
![](https://rs.olm.vn/images/avt/0.png?1311)
|5x-3|=7+x
TH1:5x-3=7+x
4x=10
x=5/2
TH2:5x-3=-7-x
6x=-4
x=-2/3.
Chúc bạn học tốt^^
|5x-3|=7+x
TH1:5x-3=7+x
4x=10
x=5/2
TH2:5x-3=-7-x
6x=-4
x=-2/3.
Chúc bạn học tốt^^
![](https://rs.olm.vn/images/avt/0.png?1311)
Nhầm Sửa lại :
\(\left|5x-3\right|-x=7\)
\(\Leftrightarrow\left|5x-3\right|=7+x\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}5x-3=7+x\\3-5x=7+x\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=\frac{5}{2}\\x=-\frac{2}{3}\end{array}\right.\)
Vậy \(x\in\left\{\frac{5}{2};-\frac{2}{3}\right\}\)
|5x-3|-x=7
=>|5x-3|=7+x
=>5x-3=-(7+x) hoặc 7+x
Xét 5x-3=-(7+x)
=>5x-3=-7-x
=>6x=-4
=>\(x=-\frac{2}{3}\)
Xét 5x-3=7+x
=>2x=5
=>\(x=\frac{5}{2}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
ko ghi đè
\(\Rightarrow\)5x-3=\(\pm\)7-x
Th15x-3=7-x
5x+x=7+3
6x=10
x=tự tính
Th2 5x-3=-(7-x)
5x-3=-7+x
5x-x=-7+3
4x=-4
x=-1
vậy x=\(\frac{3}{5}\), x=-1