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\(2^{x+3}.2=2^2.3+52\)
\(=>2^{x+3}.2=64\)
\(=>2^{x+3}=64:2\)
\(=>2^{x+3}=32\)
\(=>2^{x+3}=2^5\)
=>x+3=5
=>x=5-3
=>x=2
Vậy ...........
2x + 3 . 2 = 22 . 3 + 52
2x + 3 . 2 = 4 . 3 + 52
2x + 3 . 2 = 12 + 52
2x + 3 . 2 = 64
2x + 3 = 64 : 2
2x + 3 = 32
2x + 3 = 25
x + 3 = 5
x = 5 - 3
x = 2
Vậy x = 2
![](https://rs.olm.vn/images/avt/0.png?1311)
a. -6.x=18
<=> x=-3
Vậy x=-3
b.2.x-(-3)=7
<=> 2x=4
<=>x=2
Vậy x=2
c.(x-5).(x+6)=0
<=> x-5=0 hoặc x+6=0
<=> x=5 hoặc x=-6
Vậy \(x\in\left\{5;-6\right\}\)
Trả lời:
\(a,\)\(-6x=18\)
\(\Leftrightarrow x=-3\)
Vậy\(x=-3\)
\(b,\)\(2x-\left(-3\right)=7\)
\(\Leftrightarrow2x=4\)
\(\Leftrightarrow x=2\)
Vậy\(x=2\)
\(c,\)\(\left(x-5\right)\left(x+6\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-5=0\\x+6=0\end{cases}}\)\(\Leftrightarrow\orbr{\begin{cases}x=5\\x=-6\end{cases}}\)
Vậy\(x\in\left\{5;-6\right\}\)
Hok tốt!
Good girl
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3(x - 2) + 2x=10
3x - 6 + 2x = 10
3x + 2x = 10 + 6
5x = 16
x = 16 : 5
x = 3,2
Vậy x = 3,2
3(x-2)+2x=10
3x-6+2x=10
3x+2x=10+6
5x=16
x=16:5
x=3,2
Vậy x=3,2
![](https://rs.olm.vn/images/avt/0.png?1311)
\(2x=3y\Rightarrow\frac{x}{3}=\frac{y}{2}\Rightarrow\frac{3x}{9}=\frac{y}{2}\)
Theo t/x dãy TSBN:
\(\frac{3x}{9}=\frac{y}{2}=\frac{3x+y}{9+2}=\frac{22}{11}=2\)
=> x/3 = 2 => x = 2.3 = 6
=> y/2 = 2 => y = 2.2 = 4
Vậy x = 6; y = 4.
![](https://rs.olm.vn/images/avt/0.png?1311)
a, \(\frac{3}{4}x-\frac{1}{5}=\frac{7}{4}x+\frac{11}{5}\)
\(\Rightarrow\frac{3}{4}x-\frac{7}{4}x=\frac{11}{5}+\frac{1}{5}\)
\(\Rightarrow-x=\frac{12}{5}\Rightarrow x=-\frac{12}{5}\)
Vậy ...
b, \(\frac{x+1}{2}=\frac{8}{x+1}\)
\(\Rightarrow\left(x+1\right)^2=16\)
\(\Rightarrow x+1=4\)hoặc \(x+1=-4\)
\(\Rightarrow x=3\) hoặc \(x=-5\)
Vậy ..
3/4x-7/4x=1/5+11/5
(3/4-7/4).x=12/5
-1.x=12/5
x=12/5:-1
x=-12/5
vậy x=-12/5
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\left|x-3\right|-7=-4\)
\(\left|x-3\right|=-4+7\)
\(\left|x-3\right|=3\)
\(\Rightarrow\)\(\orbr{\begin{cases}x-3=3\\x-3=-3\end{cases}\Rightarrow\orbr{\begin{cases}x=6\\x=0\end{cases}}}\)
Vậy x=6 hoặc x=0
|x-3|-7=-4
|x-3| =-4+7
|x-3|=3
==>\(\orbr{\begin{cases}x-3=3\Rightarrow x=6\\x-3=-3\Rightarrow x=0\end{cases}}\)
Vậy x=6; x=0
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=20\times21+21\times22+...+99\times100\)
\(3\times A=20\times21\times\left(22-19\right)+21\times22\times\left(23-20\right)+...+99\times100\times\left(101-98\right)\)
\(=20\times21\times22-19\times20\times21+...+99\times100\times101-98\times99\times100\)
\(=99\times100\times101-19\times20\times21\)
Suy ra \(A=\frac{99\times100\times101-19\times20\times21}{3}=360640\)
\(B=3\times4\times5+4\times5\times6+...+98\times99\times100\)
\(4\times B=3\times4\times5\times\left(6-2\right)+4\times5\times6\times\left(7-3\right)+...+98\times99\times100\times\left(101-97\right)\)
\(=3\times4\times5\times6-2\times3\times4\times5+...+98\times99\times100\times101-97\times98\times99\times100\)
\(=98\times99\times100\times101-2\times3\times4\times5\)
Suy ra \(B=\frac{98\times99\times100\times101-2\times3\times4\times5}{4}=24497520\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) nếu \(5x-3\ge0\)hay \(x\ge\frac{3}{5}\) ta có \(\left|5x-3\right|=5x-3\)
nếu \(5x-3< 0\) hay \(x< \frac{3}{5}\) ta có \(\left|5x-3\right|=3-5x\)
với \(x\ge\frac{3}{5}\) ta có
\(\left|5x-3\right|=x+7\) \(< =>5x-3=x+7\)
\(< =>5x-x=7+3\)
\(< =>4x=10\)
\(< =>x=\frac{10}{4}=\frac{5}{2}\) (thoả mãn khoảng xét: \(\frac{5}{2}>\frac{3}{5}\))
với \(x< \frac{3}{5}\)ta được
\(\left|5x-3\right|=x+7\) \(< =>3-5x=x+7\)
\(< =>-5x-x=7-3\)
\(< =>-6x=4\)
\(< =>x=-\frac{4}{6}=-\frac{2}{3}\) (thoả mãn khoảng xét : \(-\frac{2}{3}< \frac{3}{5}\))
b) bạn lập bảng xét dấu rồi xét từng trường hợp là được
(x+3) - 2^2 *3 =-4*8
(x+3) - 12= -32
(x+3) -2=-32+12
x+3 =20
x=30-2
x=28