tìm x
a)(x+7)(3x-1)=x^2-49
b)5(x-3)-4=2(x-1)+7
NH
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tính
a)(3x-1)^2-(2x-1)(2x+1)
b)(3x-2)^2-3(2x+1)(x-2)-3x(x-1)
tìm x
a)(x+7)(3x-1)=x^2-49
b)5(x-3)-4=2(x-1)+7
tìm x
a,(x+5)(x-5)-x(x+3)=10 b,(2x+3)(2x-3)-4(x+2)^2=5
c,9x(x+5)-(3x+2)(3x-2)=7 d,(x+1)^3-x(x^2+3x-5)=8
a: =>x^2-25-x^2-3x=10
=>-3x=35
=>x=-35/3
b: =>4x^2-9-4(x^2+4x+4)=5
=>4x^2-9-4x^2-16x-16-5=0
=>-16x-30=0
=>x=-15/8
c: =>9x^2+45x-9x^2+4=7
=>45x=3
=>x=1/15
d: =>x^3+3x^2+3x+1-x^3-3x^2+5x=8
=>8x=7
=>x=7/8
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Bài 1: Tìm x :
a. ( x + 4 )2 - ( x + 1 ) ( x - 1 ) = 16
b. ( 2x - 1 )2 + ( x + 3 )2 - 5 ( x + 7 ) ( x - 7 ) = 0
c. ( x - 2 )3 - ( x - 3 ) ( x2 + 3x + 9 ) + 6 ( x + 1 )2 = 49
Bài 1: Tìm x :
a. ( x + 4 )2 - ( x + 1 ) ( x - 1 ) = 16
b. ( 2x - 1 )2 + ( x + 3 )2 - 5 ( x + 7 ) ( x - 7 ) = 0
c. ( x - 2 )3 - ( x - 3 ) ( x2 + 3x + 9 ) + 6 ( x + 1 )2 = 49
Tìm x
a) 6x(5x + 3) + 3x(1 – 10x) = 7 b) (3x – 3)(5 – 21x) + (7x + 4)(9x – 5) = 44
c) (x + 1)(x + 2)(x + 5) – x2(x + 8) = 27
d) 5x(12x + 7) – 3x(20x – 5) = - 100
e) 0,6x(x – 0,5) – 0,3x(2x + 1,3) = 0,138
a) 6x(5x + 3) + 3x(1 – 10x) = 7
⇒ 30x2+18x+3x-30x2=7
⇒21x=7
⇒x=\(\dfrac{7}{21}\)
⇒x= \(\dfrac{1}{3}\)
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b) (3x – 3)(5 – 21x) + (7x + 4)(9x – 5) = 44
⇒15x-63x2-15+63x + 63x2-35x+36x-20=44
⇒79x-35=44
⇒79x=44+35
⇒79x=79
⇒x=1
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d) 5x(12x + 7) – 3x(20x – 5) = - 100
⇒60x2+35x-60x2+15=-100
⇒35x+15=-100
⇒35x=-100-15
⇒35x=-115
⇒x=\(\dfrac{-115}{35}\)
⇒x=\(\dfrac{-23}{7}\)
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bài 1 : Tìm x
a) 5 + ( x + 27 ) = 64
b) 64 - ( x - 2 ) = 25
c) 7 - ( x + 5 ) + 14 = 343
d) 5 . x - 25 = 10
e) 4 . ( x - 5 ) - 8 = 48
f) 49 - ( 15 + x ) = 12
g) 49 - 7. ( 13 - x ) = 14
h) 155 - 10. ( x + 1 ) = 55
5 + ( x + 27 ) = 64
( x + 27 ) = 64 - 5 ( x + 27 ) = 59 x = 59 - 27 x = 32
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a) \(\Rightarrow x+27=59\Rightarrow x=32\)
b) \(\Rightarrow x-2=39\Rightarrow x=41\)
c) \(\Rightarrow x+5=-322\Rightarrow x=-327\)
d) \(\Rightarrow5x=35\Rightarrow x=7\)
e) \(\Rightarrow4\left(x-5\right)=56\Rightarrow x-5=14\Rightarrow x=19\)
f) \(\Rightarrow15+x=37\Rightarrow x=22\)
g) \(\Rightarrow7\left(13-x\right)=35\Rightarrow13-x=5\Rightarrow x=8\)
h) \(\Rightarrow10\left(x+1\right)=100\Rightarrow x+1=10\Rightarrow x=9\)
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tìm x
a,(x+1)^3-(x-1)^3-6(x-1)^2=-10
b,x(x+5)(x-5)-(x+2)(x^2-2x+4)=42
c,(x-2)^3-(x-3)(x^2+3x+9)+6(x+1)^2=49
a) \(\left(x+1\right)^3-\left(x-1\right)^3-6\cdot\left(x-1\right)^2=10\)
\(\Rightarrow x^3+3x^2+3x+1-x^3+3x^2-3x+1-6\cdot\left(x^2-2x+1\right)=10\)
\(\Rightarrow6x^2+2-6x^2+12x-6=10\)
\(\Rightarrow12x-4=10\)
\(\Rightarrow12x=14\)
\(\Rightarrow x=\dfrac{7}{6}\)
b) \(x\left(x+5\right)\left(x-5\right)-\left(x+2\right)\left(x^2-2x+4\right)=42\)
\(\Rightarrow x\left(x^2-25\right)-\left(x^3+8\right)=42\)
\(\Rightarrow x^3-25x-x^3-8=42\)
\(\Rightarrow-25x-8=42\)
\(\Rightarrow-25x=50\)
\(\Rightarrow x=\dfrac{50}{-25}=-2\)
c) \(\left(x-2\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2=49\)
\(\Rightarrow x^3-6x^2+12x-8-\left(x^3-27\right)+6\left(x^2+2x+1\right)=49\)
\(\Rightarrow x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=49\)
\(\Rightarrow24x+25=49\)
\(\Rightarrow24x=24\)
\(\Rightarrow x=\dfrac{24}{24}=1\)
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tìm x
a)(x+7)(3x-1)=x^2-49
b)5(x-3)-4=2(x-1)+7
tính
a)(3x-1)^2-(2x-1)(2x+1)
b)(3x-2)^2-3(2x+1)(x-2)-3x(x-1)
tìm x
a)(x+7)(3x-1)=x^2-49
b)5(x-3)-4=2(x-1)+7
\(a.\left(x+7\right)\left(3x-1\right)=x^2-49\Leftrightarrow\left(x+7\right)\left(3x-1\right)=\left(x-7\right)\left(x+7\right)\Rightarrow3x-1=x-7\Rightarrow3x-x=-7+1\Rightarrow2x=-6\Rightarrow x=-3\)
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