Tìm x:
a)x-12=-20
b)2014.(x-12)=0
c)23-3x=17
d)50-(x-3)=45
Tìm x
a.4x-12=-20
b.2014(x-12)=0
c. 23-3x=17
d.50-(x-3)=45
a, \(4x-12=-20\)
\(4x=-8\)
\(x=-2\)
Vậy...
b, \(2014\left(x-12\right)=0\)
\(x-12=0\)
\(x=12\)
Vậy....
c, \(23-3x=17\)
\(3x=6\)
\(x=2\)
Vậy........
d, \(50-\left(x-3\right)=45\)
\(x-3=5\)
\(x=8\)
Vậy....
a, x- 12 = -20
b, 2014( x -12 ) = 0
c , 23 - 3x = 17
d , 50 - ( x - 3)
a) x-12=(-20)
=> x=(-20)+12
=> x=(-8)
b) 2014(x-12)=0
=> x-12=0
=>x=0+12
=> x=12
c) 23-3x=17
=> 3x=23-17
=> 3x=6
=> x=2
d) Câu này thiếu dữ liệu bạn nhé
=câu d là 50- ( x- 12 ) = 45
sorry giúp minh nhé cảm ơn bạn
Bài 2: Tìm x:
a) 156 – (x+ 61) = 82 b) (x-35) -120 = 0 c) 124 + (118 – x) = 217 d) 7x – 8 = 713 e) x- 36:18 = 12 f) (x- 36):18 = 12 g) (x-47) -115 = 0 |
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Bài 3: Tính nhanh
a) 58.75 + 58.50 – 58.25 b) 27.39 + 27.63 – 2.27 c) 128.46 + 128.32 + 128.22 d) 66.25 + 5.66 + 66.14 + 33.66 e) 12.35 + 35.182 – 35.94 | f) 48.19 + 48.115 + 134.52 g) 27.121 – 87.27 + 73.34 h) 125.98 – 125.46 – 52.25 i) 136.23 + 136.17 – 40.36 j) 17.93 + 116.83 + 17.23 | k) 35.23 + 35.41 + 64.65 l) 29.87 – 29.23 + 64.71 m) 19.27 + 47.81 + 19.20
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Bài 4: Tính giá trị của biểu thức sau:
a) 2763 + 152 b) (-7) + (-14) c) (-35) + (-9) d) (-5) + (-248) e) (-23) + 105 f) 78 + (-123) g) 23 + (-13) h) (-23) + 13 i) 26 + (-6) | j) 80 + (-220) k) (-23) + (-13) l) (-26) + (-6) | m) 12 – 34 n) -23 – 47 o) 31 – (-23) p) -9 – (-5) q) 6 – (8 – 17) r) 19 + (23 – 33) s) (-12 – 44) + (-3) t) 4 – (-15) u) -29 – 23 | v) 99 – [109 + (-9)] w) (-75) + 50 x) (-75) + (-50) y) (-23) + 13 + ( - 17) + 57 z) 14 + 6 + (-9) + (-14)
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a: =>x+61=74
hay x=13
b: =>x-35=120
hay x=155
d: =>7x=721
hay x=103
Tìm x:
a)(x+3)2-4x-12=0
b)x(x+5)(x-5)-(x-3)(x2+3x+9)=7
a) (x + 3)^2 - 4x - 12 = 0
<=> (x + 3)^2 - 4(x + 3) = 0
<=> (x + 3)(x - 1) = 0
<=> x = -3 hoặc x = 1
b) x(x + 5)(x- 5) - (x - 3)(x^2 + 3x + 9) = 7
<=> x^3 - 25x - x^3 + 27 = 7
<=> -25x + 27 = 7
<=> x = 4/5
a/ \(\left(x+3\right)^2-4x-12=0\)
\(\left(x+3\right)^2-4\left(x+3\right)=0\)
\(\left(x+3\right)\left(x+3-4\right)=0\)
\(\left[{}\begin{matrix}x+3=0\Rightarrow x=-3\\x+3-4=0\Rightarrow x=1\end{matrix}\right.\)
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b/ \(x\left(x+5\right)\left(x-5\right)-\left(x-3\right)\left(x^2+3x+9\right)=7\)
\(x\left(x^2-25\right)-\left(x^3-27\right)=7\)
\(x^3-25x-x^3+27=7\)
\(-25x=-20\)
\(x=\dfrac{20}{25}=\dfrac{4}{5}\)
a, <=>x2 +6x+9-4x-12=0
<=> x2 +2x -3=0
<=> x2 +3x -x-3=0
<=> x.(x+3) - (x+3) =0
<=> (x-1)(x+3)=0
<=> x=1 hoặc x=-3
b, <=> x(x2 -25) - (x-3)(x+3)2 -7=0
<=> x3 -25x + (9-x2) (x+3) -7=0
<=> x3 -25x+ 9x+27-x3 -3x2 -7=0
<=> -3x2 -16x +20=0
<=>(3x-10)(x-2) =0 (đoạn này tự phân tích nha ^ ^)
<=> x= 10/3 hoặc x=2
Chúc bạn học tốt nha!
Tìm x:
a) (2x - 1) (x^2 - x + 1) = 2x^3 - 3x^2 + 2
b) (x + 1) (x^2 + 2x + 4) - x^3 - 3x^2 + 16 = 0
c) (x + 1) (x + 2) (x + 5) - x^3 - 8x^2 = 27
a) Ta có: \(\left(2x-1\right)\left(x^2-x+1\right)=2x^3-3x^2+2\)
\(\Leftrightarrow2x^3-2x^2+2x-x^2+x-1-2x^3+3x^2-2=0\)
\(\Leftrightarrow3x=3\)
hay x=1
Vậy: S={1}
b) Ta có: \(\left(x+1\right)\left(x^2+2x+4\right)-x^3-3x^2+16=0\)
\(\Leftrightarrow x^3+2x^2+4x+x^2+2x+4-x^3-3x^2+16=0\)
\(\Leftrightarrow6x=-20\)
hay \(x=-\dfrac{10}{3}\)
c) Ta có: \(\left(x+1\right)\cdot\left(x+2\right)\left(x+5\right)-x^3-8x^2=27\)
\(\Leftrightarrow\left(x^2+3x+2\right)\left(x+5\right)-x^3-8x^2-27=0\)
\(\Leftrightarrow x^3+5x^2+3x^2+15x+2x+10-x^3-8x^2-27=0\)
\(\Leftrightarrow17x=17\)
hay x=1
Tìm x:
a) x(x-1)+x=4
b) 3x(x-5)-2x+10=0
c) 5x2-3x-2=0
d) x4-11x2+18=0
a) \(x^2-x+x=4\)
\(x^2=4\)
\(x=\pm2\)
b) \(3x\left(x-5\right)-2\left(x-5\right)=0\)
\(\left(x-5\right)\left(3x-2\right)=0\)
\(\left[{}\begin{matrix}x=5\\x=\dfrac{2}{3}\end{matrix}\right.\)
c) Ta có: \(a+b+c=5-3-2=0\)
\(\left[{}\begin{matrix}x=1\\x=\dfrac{c}{a}=\dfrac{-2}{5}\end{matrix}\right.\)
d) Đặt \(x^2=t\left(t\ge0\right)\) . Lúc đó phương trình trở thành :
\(t^2-11t+18=0\)
\(\left[{}\begin{matrix}t=9\left(tmđk\right)\\t=2\left(tmđk\right)\end{matrix}\right.\)
\(t=9\rightarrow x^2=9\rightarrow x=\pm3\)
\(t=2\rightarrow x^2=2\rightarrow x=\pm\sqrt{2}\)
Tìm x:
a)(x+2)^2-2(x+2)(x-5)=0
b)2x^2+3x-5=0
c)x+2√2x^2+2x^3=0
d)(3x-1)^2-4(x+5)^2=0
a: \(\Leftrightarrow\left(x+2\right)\left(12-x\right)=0\)
\(\Leftrightarrow x\in\left\{-2;12\right\}\)
b: \(\Leftrightarrow\left(2x+5\right)\left(x-1\right)=0\)
\(\Leftrightarrow x\in\left\{-\dfrac{5}{2};1\right\}\)
Tìm x:
a) 27x3-27x2+9x-1=\(\dfrac{-1}{8}\)
b) x(4-x)+(2x-1)(x-4)=0
c) 3x(5x-2)-10x+4=0
a.
\(\Leftrightarrow\left(3x-1\right)^3=\left(-\dfrac{1}{2}\right)^3\)
\(\Leftrightarrow3x-1=-\dfrac{1}{2}\)
\(\Leftrightarrow3x=\dfrac{1}{2}\)
\(\Leftrightarrow x=\dfrac{1}{6}\)
b.
\(\Leftrightarrow\left(2x-1\right)\left(x-4\right)-x\left(x-4\right)=0\)
\(\Leftrightarrow\left(x-4\right)\left(2x-1-x\right)=0\)
\(\Leftrightarrow\left(2x-1\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=\dfrac{1}{2}\\\end{matrix}\right.\)
c.
\(\Leftrightarrow3x\left(5x-2\right)-2\left(5x-2\right)=0\)
\(\Leftrightarrow\left(3x-2\right)\left(5x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=\dfrac{2}{5}\end{matrix}\right.\)
2. Tìm x:
a) 4/5 + x = 2/3
b) 1/2 - x = 7/12
c) 3 và 1/2 : x = -7/2
d) 3/8 - 1/6 x =5/2
e) x + 50%x = -1,5
a: x=2/3-4/5=10/15-12/15=-2/15
b: 1/2-x=7/12
=>x=1/2-7/12=-1/12
c: =>7/2:x=-7/2
=>x=-1
d: =>1/6x=3/8-5/2=3/8-20/8=-17/8
=>x=-17/8*6=-102/8=-51/4
e: =>1,5x=-1,5
=>x=-1