Tìm x:
a, | x - 3 | = 2x + 4
b, | 2x + 1 | = x - 2
c, | x + 3 | + | x + 2 | = 6
Những câu hỏi liên quan
Bài 1 : Tìm thương Q và dư R sao cho A B.Q+R biết ;a) A x^4+3x^3+2x^2-x-4 và B x^2-2x+3b) A 2x^3-3x^2+6x-4 và B x^2-x+3c) A 2x^4+x^3+3x^2+4x+9 và B x^2+1d) A 2x^3-11x^2+19x-6 và B x^2-3x+1c) A 2x^4-x^3-x^2-x+1 và B x^2+1
Đọc tiếp
Bài 1 : Tìm thương Q và dư R sao cho A= B.Q+R biết ;
a) A = \(x^4+3x^3+2x^2-x-4\) và B = \(x^2-2x+3\)
b) A = \(2x^3-3x^2+6x-4\) và B = \(x^2-x+3\)
c) A = \(2x^4+x^3+3x^2+4x+9\) và B = \(x^2+1\)
d) A = \(2x^3-11x^2+19x-6\) và B = \(x^2-3x+1\)
c) A= \(2x^4-x^3-x^2-x+1\) và B = \(x^2+1\)
Tìm x :
a) (2x-1)3-4x2 . (2x-3)=5
b) (x+1)3-(x-1)3-6.(x+1)2=-10
c) (x+2)3-x2.(x+6)=4
a) \(\left(2x-1\right)^3-4x^2\left(2x-3\right)=5\)
\(\Leftrightarrow8x^3-12x^2+6x-1-8x^3+12x^2=5\)
\(\Leftrightarrow6x-1=5\Leftrightarrow6x=6\Leftrightarrow x=1\)
b) \(\left(x+1\right)^3-\left(x-1\right)^3-6\left(x+1\right)^2=-10\)
\(\Leftrightarrow\left(x+1-x+1\right)\left[\left(x^2+2x+1+x^2-2x+1+\left(x^2-1\right)\right)\right]-6\left(x^2+2x+1\right)=-10\)
\(\Leftrightarrow2\left(3x^2+1\right)-6x^2-12x-6=-10\)
\(\Leftrightarrow6x^2+2-6x^2-12x-6=-10\)
\(\Leftrightarrow-12x-4=-10\Leftrightarrow12x=-6\Leftrightarrow x=\dfrac{1}{2}\)
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Câu 3: Tìm x ∈ N, biết:
a) 3 x . 3 = 243 b) 2 x . 162 = 1024 c) 64.4x = 168 d) 2 x = 16Câu 4 : Tìm x, biết. a) 2 x .4 = 128 b) (2x + 1)3 = 125 c) 2x – 2 6 = 6 d) 49.7x = 2401
3:
a: 3^x*3=243
=>3^x=81
=>x=4
b; 2^x*16^2=1024
=>2^x=4
=>x=2
c: 64*4^x=16^8
=>4^x=4^16/4^3=4^13
=>x=13
d: 2^x=16
=>2^x=2^4
=>x=4
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1,tìm x a) (x+3)^2-(x-2)^3=(x+5)(x^2-5x+25)-108 b) 4(x^2+2x-1)^2-(2x^2-3)^2=0 c) (2x-1)(4x^2+2x+1)-(x-2)^2=-x(x-6)-5
a) \(\left(x+3\right)^2-\left(x-2\right)^3=\left(x+5\right)\left(x^2-5x+25\right)-108\)
\(\Leftrightarrow x^2+6x+9-x^2+4x-4=x^3-5x^2+25x+5x^2-25x+125-108\)
\(\Leftrightarrow x^3-10x+12=0\Leftrightarrow\left(x-2\right)\left(x^2+2x+6\right)=0\)
\(\Leftrightarrow x=2\)( do \(x^2+2x+6=\left(x+1\right)^2+4\ge4>0\))
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Tìm x biết:
a,2x(x+1)-3-2x=5
b,2x(3x+1)+(4-2x)=7\
c,(x-3)^3-(x-3)(x^2+3x+9)+6(x-1)^2=6
a)\(2x\left(x+1\right)-3-2x=5\)
\(\Leftrightarrow2x^2+2x-3-2x=5\)
\(\Leftrightarrow2x^2=8\)
\(\Leftrightarrow x^2=4=\left(-2\right)^2=2^2\)
\(\Rightarrow x=2;-2\)
b)\(2x\left(3x+1\right)+\left(4-2x\right)=7\)
\(\Leftrightarrow6x^2+2x+4-2x=7\)
\(\Leftrightarrow6x^2+4=7\)
\(\Leftrightarrow6x^2=3\)
\(\Leftrightarrow x^2=\frac{1}{2}=-\sqrt{\frac{1}{2}}=\sqrt{\frac{1}{2}}\)
c)\(\left(x-3\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x-1\right)^2=6\)
\(\Leftrightarrow x^3-9x^2+27x-27-x^3+27+6\left(x^2-2x+1\right)=6\)
\(\Leftrightarrow-3x^2+27x+6x^2-12x+6=6\)
\(\Leftrightarrow-3x^2+27x+6x^2-12x+6=6\)
\(\Leftrightarrow3x^2+15x=0\)
\(\Leftrightarrow3x\left(x+5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}3x=0\\x+5=0\end{cases}\Rightarrow}\orbr{\begin{cases}x=0\\x=-5\end{cases}}\)
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Tìm x biết:
a,2x(x+1)-3-2x=5
b.2x(3x+1)+(4-2x)=7
c,(x-3)^3-(x-3)(x^2+3x+9)+6(x-1)^2=6
Tìm x biết:
a; 3x.(2x+3)-(2x+5x).(3x-2)=8
b;4.(x-1)-3.(x^2-5)_x^2=(x-3)-(x+4)
c; 2.(3x-1).(2x+5)-6.(2x-1).(x+2)=-6
d; 3.(2x-1).(3x-1)-(2x-3.(9x-1)-3=3
5: Tìm x biết a) x/3 =4/12 b) x-1/ x-2=3/5 c) 2x :6=1/4 d) x² +x/2x²+1=1/2
a) \(\dfrac{x}{3}=\dfrac{4}{12}\Rightarrow x=\dfrac{4}{12}\cdot3=\dfrac{12}{12}=1\)
b) \(\dfrac{x-1}{x-2}=\dfrac{3}{5}\) (Điều kiện : \(x\ne2\))
\(\Rightarrow5\left(x-1\right)=3\left(x-2\right)\)
\(\Leftrightarrow5x-5=3x-6\Leftrightarrow5x-3x=-6+5\Leftrightarrow2x=-1\Leftrightarrow x=-\dfrac{1}{2}\)
c) \(2x:6=\dfrac{1}{4}\Leftrightarrow2x=\dfrac{1}{4}\cdot6=\dfrac{6}{4}=\dfrac{3}{2}\Leftrightarrow x=\dfrac{3}{2}:2=\dfrac{3}{2}\cdot\dfrac{1}{2}=\dfrac{3}{4}\)
d) \(\dfrac{x^2+x}{2x^2+1}=\dfrac{1}{2}\)
\(\Rightarrow2\left(x^2+x\right)=2x^2+1\)
\(\Leftrightarrow2x^2+2x=2x^2+1\)
\(\Leftrightarrow2x^2+2x-2x^2=1\Leftrightarrow2x=1\Leftrightarrow x=\dfrac{1}{2}\).
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tìm x
a) ( 2x - 3 ) * ( x + 1 ) - x ( 2x + 3 ) - 9 = 0'
b) 2x ( x - 3 ) - x - 3 = 0
c) 2x * ( x^2 - 4 ) + 6 ( 4 - x^2)=0
Answer:
\(\left(2x-3\right).\left(x+1\right)-x.\left(2x+3\right)-9=0\)
\(\Rightarrow\left(2x^2+2x-3x-3\right)-2x^2-3x-9=0\)
\(\Rightarrow\left(2x^2-x-3\right)-2x^2-3x-9=0\)
\(\Rightarrow2x^2-x-3-2x^2-3x-9=0\)
\(\Rightarrow\left(2x^2-2x^2\right)-\left(x+3x\right)-\left(3+9\right)=0\)
\(\Rightarrow-4x-12=0\)
\(\Rightarrow x+3=0\)
\(\Rightarrow x=-3\)
\(2x.\left(x-3\right)-x+3=0\) (Sửa đề)
\(\Rightarrow2x.\left(x-3\right)-\left(x-3\right)=0\)
\(\Rightarrow\left(x-3\right).\left(2x-1\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\2x-1=0\end{cases}\Rightarrow\orbr{\begin{cases}x=3\\2x=1\end{cases}}\Rightarrow\orbr{\begin{cases}x=3\\x=\frac{1}{2}\end{cases}}}\)
\(2x.\left(x^2-4\right)+6.\left(4-x^2\right)=0\)
\(\Rightarrow2x.\left(x^2-4\right)-6.\left(x^2-4\right)=0\)
\(\Rightarrow2.\left(x-3\right).\left(x+2\right).\left(x-2\right)=0\)
Trường hợp 1: \(x-3=0\Rightarrow x=3\)
Trường hợp 2: \(x+2=0\Rightarrow x=-2\)
Trường hợp 3: \(x-2=0\Rightarrow x=2\)
tìm Min: a,|2x+1|+|2x+2|+|2x+3|+|2x+4|
b,|x-2|+|x-3|+|x-4|+|x-5|+|x-6|
c,|x-2|+|x-3|+|x-4|+|x-10|
d,|x+1|+|x+2|+|x+3|+|x+4|+|x+5|+|x+6|
giúp mình nha, mình cần gấp lắm