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a) x-12=(-28)
x=(-28)+12
x=(-16)
Vậy x=(-16)
b)20+8|x-3|=52.4
20+8|x-3|=100
8|x-3|=100-20
8|x-3|=80
|x-3|=80:8
|x-3|=10
=>x-3=10 hoặc x-3=(-10)
x=10+3 x=(-10)+3
x=13 x=(-7)
Vậy x thuộc {13;-7}
c) 96-3(x+1)=42
3(x+1)=96-42
3(x+1)54
x+1=54:3
x+1=18
x=18-1
x=17
Vậy x=17
|x-3|=7-(-2)
|x-3|=9
=>x-3=9 hoặc x-3=(-9)
x=9+3 x=(-9)+3
x=12 x=(-6)
Vậy...
e) (2x-1)3=125
(2x-1)3=53
=>2x-1=5
...
Còn lại tự lm nha
Câu g tương tự câu e
Nhiều câu quá >.<
a/ \(2x\left(x+5\right)=\left(x+3\right)^2+\left(x-1\right)^2+20.\)
\(2x^2+10x=x^2+6x+9+x^2-2x+1+20.\)
\(10x=4x+30\)
\(6x=30\Rightarrow x=5\)
các câu còn lại tương tự
\(a,2x\left(x+5\right)=\left(x+3\right)^2+\left(x-1\right)^2+20\)
\(\Leftrightarrow2x^2+10x=x^2+6x+9+x^2-2x+1+20\)
\(\Leftrightarrow2x^2+10x=2x^2+4x+30\)
\(\Leftrightarrow2x^2+10x-2x^2-4x=30\)
\(\Leftrightarrow6x=30\)
\(\Leftrightarrow x=5\)
Vậy ...........
\(b,\left(2x-2\right)^2=\left(x+1\right)^2+3\left(x-2\right)\left(x+5\right)\)
\(\Leftrightarrow4x^2-8x+4=x^2+2x+1+3x^2+15x-6x-30\)
\(\Leftrightarrow4x^2-8x+4=4x^2+11x-29\)
\(\Leftrightarrow4x^2-8x-4x^2-11x=-29-4\)
\(\Leftrightarrow-19x=-33\)
\(\Leftrightarrow x=\frac{33}{19}\)
Vậy...........
\(c,\left(x-1\right)^2+\left(x+3\right)^2=2\left(x-2\right)\left(x+1\right)+38\)
\(\Leftrightarrow x^2-2x+1+x^2+6x+9=2x^2+2x-4x-4+38\)
\(\Leftrightarrow2x^2+4x+10=2x^2-2x+34\)
\(\Leftrightarrow2x^2+4x-2x^2+2x=34-10\)
\(\Leftrightarrow6x=24\)
\(\Leftrightarrow x=4\)
Vậy.............
\(d,\left(x+2\right)^3-\left(x-2\right)^3=12x\left(x-1\right)-18\)
\(\Leftrightarrow x^3+6x+12x+8-\left(x^3-6x+12x-8\right)=12x^2-12x-8\)
\(\Leftrightarrow x^3+6x+12x+8-x^3+6x-12x+8=12x^2-12x-8\)
\(\Leftrightarrow12x=-24\)
\(\Leftrightarrow x=-2\)
Vậy............
A, (2367-x) - (210- 7) = 152 - 20
(2367-x) - (1024- 7) = 255 - 20
(2367-x) - 1017 = 205
2367-x=205+1017
2367-x=1222
x=2367-1222
x=1145
B, 8.6+288: (x-3)2 = 50
48+288:(x-3)2 = 50
288: (x-3)2 = 50-48
288: (x-3)2 = 2
(x-3)2 =288:2
(x-3)2 =144
(x-3)2 =122
x-3=12
x=12+3
x=15
D, 10+2x=45: 43
10+2x=45-3
10+2x=42
10+2x=16
2x=16-10
2x=6
x=6:2
x=3
Bài 1:
a) 6/2 x+ 1 = 2/7
6/2 x = 2/7 - 1
6/2 x = 2/7 - 7/7
6/2 x = -5/7
x = - 5/7 : 6/2
x = - 5/7 . 2/6
x = -5/21
Ủng hộ nha! :)
BÀI 1 a 6/2x+1=2/7
6/2x=2/7-1
6/2x=-5/7
6*7=5*2x
42=5*2x
42/5=2x
x=42/5:2
x=21/5
a. 3.x+7=25
<=> 3x = 18
<=> x = 6
b. (5.x+4)-1=23
<=> 5x + 4 = 24
<=> 5x = 20
<=> x = 4
c. 96-3(x+1)=42
<=> 3(x + 1) = 54
<=> x + 1 = 18
<=> x = 17
d. 2x=16
<=> 2x = 24
<=> x = 4
e. x2=16
<=> \(\orbr{\begin{cases}x^2=4^2\\x^2=\left(-4\right)^2\end{cases}}\)
<=> x = \(\pm\)4
a, \(15:\left(x+2\right)=3\Leftrightarrow x+2=3\Leftrightarrow x=1\)
b, \(20:\left(x+1\right)=2\Leftrightarrow x+1=10\Leftrightarrow x=9\)
c, \(240:\left(x-5\right)=2^2.5^2-20=80\Leftrightarrow x-5=3\Leftrightarrow x=8\)
d, \(96-3\left(x+1\right)=42\Leftrightarrow3\left(x+1\right)=54\Leftrightarrow x+1=18\Leftrightarrow x=17\)
a) 15 : (x + 2) = 3
x + 2 = 15 : 3
x + 2 = 5
x = 5 – 2 = 3
b) 20 : (1 + x) = 2
1 + x = 20 : 2
1 + x = 10
x = 10 – 1 = 9
c) 240 : (x – 5) = 22.52 – 20
240 : (x – 5) = 4.25 – 20
240 : (x - 5) = 100 – 20
240 : (x - 5) = 80
x – 5 = 240 : 80
x – 5 = 3
x = 3 + 5 = 8
d) 96 - 3(x + 1) = 42
3(x + 1) = 96 – 42
3(x + 1) = 54
x + 1 = 54 : 3
x + 1 = 18
x = 18 – 1
x = 17
\(15\div\left(x+2\right)=3\) \(20\div\left(1+x\right)=2\)
\(x+2=15\div3\) \(1+x=20\div2\)
\(x+2=5\) 1+x=10
x = 5 - 2 x=9
x = 3
\(240\div\left(x-5\right)=2^2\cdot5^2-20\) \(96-3\left(x+1\right)=42\)
\(240\div\left(x-5\right)=80\) \(3\left(x+1\right)=96-42\)
\(x-5=240\div80\) \(3\left(x+1\right)=54\)
x-5=3 \(x+1=54\div3\)
x=8 x+1=18
x=17
a) 15 : (x + 2) = 3
x + 2 = 15 : 3
x + 2 = 5
x = 5 - 2
x = 3
Vậy x = 3
b) 20 : (1 + x) = 2
1 + x = 20 : 2
1 + x = 10
x = 10 -1
x = 9
Vậy x = 9
c) 240 : (x – 5) = 22.52 – 20
240 : (x – 5) = 80
x – 5 = 240 : 80
x – 5 = 3
x = 3 + 5
x = 8
Vậy x = 8
d) 96 - 3(x + 1) = 42
- 3(x + 1) = 96 - 42
- 3(x + 1) = 54
x + 1 = 54 : (-3)
x + 1 = -18
x = -18 - 1
x = -19
Vậy x = -19
a) \(15:\left(x+2\right)=3\)
\(\Rightarrow x+2=15:3=5\\ \Rightarrow x=5-2=3\)
b)\(20:\left(1+x\right)=2\\ \Rightarrow1+x=20:2=10\\ \Rightarrow x=10-1=9\)
c)\(\text{240 : (x – 5) = 2^2 * 5^2 – 20 }\\\text{240 : (x – 5) = 80 }\\ \Rightarrow x-5=240:80=3\\ \Rightarrow x=3+5=8 \)
d)\(\text{ 96 - 3(x + 1) = 42}\\ \Rightarrow3\left(x+1\right)=96-42=54\\ \Rightarrow x+1=54:3=18\\ \Rightarrow x=18-1=17\)