Tìm x biết
a, |2x-1|+|2x-5|=4
Tìm số tự nhiên x, biết:
a) ( x + 1 ) 4 = ( 2 x ) 4 ;
b) ( 2 x - 1 ) 5 = x 5
a) Ta có: ( x + 1 ) 4 = ( 2 x ) 4 nên x +1 = 2x. Do đó x = 1.
b) Ta có: ( 2 x - l ) 5 = x 5 nên 2x - l = x. Do đó x = l.
Tìm x, biết:
a) 5(3x+5)-4(2x-3) = 5x+8(2x+12)+1
b) (2x+3)(x-4)-(3x-5)(x-4) = (5-x).(x-2)
\(a,5\left(3x+5\right)-4\left(2x-3\right)=5x+8\left(2x+12\right)+1\)
\(\Rightarrow5\left(3x+5\right)-4\left(2x-3\right)-5x-8\left(2x+12\right)-1=0\)
\(\Rightarrow15x+25-8x+12-5x-16x-96-1=0\)
\(\Rightarrow-14x-60=0\)
\(\Rightarrow-14x=60\) \(\Rightarrow x=-\frac{60}{14}=\frac{-30}{7}\)
\(b,\left(2x+3\right)\left(x-4\right)-\left(3x-5\right)\left(x-4\right)=\left(5-x\right)\left(x-2\right)\)
\(\Rightarrow2x^2+3x-8x-12-3x^2+5x+12x-20=5x-x^2-10+2x\)
\(\Rightarrow-x^2+12x-32=7x-x^2-10\)
\(\Rightarrow-x^2+12x-32-7x+x^2+10=0\)
\(\Rightarrow5x-22=0\)
\(\Rightarrow5x=22\Rightarrow x=\frac{22}{5}\)
a) 5(3x+5)-4(2x-3) = 5x+8(2x+12)+1
15x + 25 - 8x + 12 = 5x + 16x + 96 + 1
15x - 8x - 5x - 16x = 96 + 1 - 25 - 12
-14x = 60
x = \(\frac{60}{-14}\)
x = \(-\frac{30}{7}\)
b) (2x+3)(x-4)-(3x-5)(x-4) = (5-x).(x-2)
(x - 4)(2x + 3 - 3x +5) = 5x - 10 - x2 + 2x
(x - 4)[(2x - 3x) + (3 + 5)] = 5x - 10 - x2 + 2x
(x - 4)(-x + 8) = 5x - 10 - x2 + 2x
-x2 + 8x + 4x - 32 = 5x - 10 - x2 + 2x
(-x2 + x2) + (8x + 4x - 5x - 2x) = -10 + 32
5x = 22
x = \(\frac{22}{5}\)
a) 5(3x+5)-4(2x-3)=5x+8(2x+12)+1
<=> 15x+25-8x+12=5x+16x+96+1
<=>15x-8x-5x-16x=-25-12+96+1
<=> -14x = 60
<=> x= \(\frac{-60}{14}\)=\(\frac{-30}{7}\)
Vậy x= \(\frac{-30}{7}\)
tìm x biết
a,2x-5=3+2x-7x
c,(2x-1)^2 )=(2x-1)^5
b,1/5×-3y=4-3y
d,3×(2x+5)-4×(x-7)=8×(2-3x)
a) 2x-5=3+2x-7x
2x-2x+7x=3+5
7x=8
x=8/7
vậy x=8/7
a) 2x - 5 = 3 + 2x - 7x
=> 2x - 2x + 7x = 3 +5
=> 7x = 8
=> x = 8/7
b) \(\left(2x-1\right)^2=\left(2x-1\right)^5\)
=> \(\left(2x-1\right)^2-\left(2x-1\right)^5=0\)
=> \(\left(2x-1\right)^2\left[1-\left(2x-1\right)^3\right]=0\)
=> \(\orbr{\begin{cases}\left(2x-1\right)^2=0\\1-\left(2x-1\right)^3=0\end{cases}}\)
=> \(\orbr{\begin{cases}2x-1=0\\\left(2x-1\right)^3=1\end{cases}}\)
=> \(\orbr{\begin{cases}2x=1\\2x-1=1\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{1}{2}\\2x=2\end{cases}}\)
=> \(\orbr{\begin{cases}x=\frac{1}{2}\\x=1\end{cases}}\)
tìm x biết
a,x-5-(-4)-2x=-1-2-(-3)
b,2x-(-5)-x+(-4)=-5-(-5)
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) \(\dfrac{x^2+x}{2x^2+1}=\dfrac{1}{2}\)
\(\Rightarrow2\left(x^2+x\right)=2x^2+1\)
\(\Leftrightarrow2x^2+2x=2x^2+1\)
\(\Leftrightarrow2x^2+2x-2x^2=1\Leftrightarrow2x=1\Leftrightarrow x=\dfrac{1}{2}\).
a)
(2x-1)2-(5x-5)2=0
<=>(2x-1-5x+5)(2x-1+5x-5)=0
<=>(-3x+4)(7x-6)=0
<=>\(\orbr{\begin{cases}-3x+4=0\\7x-6=0\end{cases}}\)
<=>\(\orbr{\begin{cases}-3x=-4\\7x=6\end{cases}}\)
<=>\(\orbr{\begin{cases}x=\frac{-4}{-3}=\frac{4}{3}\\x=\frac{6}{7}\end{cases}}\)
b)
(2x+1)2-4(x+3)2=0
<=>(2x+1)2-[2(x+3)]2=0
<=>(2x+1)2-(2x+6)2=0
<=>(2x+1-2x-6)(2x+1+2x+6)=0
<=>-5(4x+7)=0
<=>4x+7=0
<=>4x=-7
<=>\(x=-\frac{7}{4}\)
a) 5(2x -1) - 4(8 - 3x) = 7
<=> 10x - 5 - 32 + 12x = 7
<=> 22x = 44
<=> x =2
Vậy x = 2 là nghiệm phương trình
b) 7(2x - 5) - 5(7x - 2) + 2(5x - 7) = (x - 2) - (x + 4)
<=> 14x - 35 - 35x + 10 + 10x - 14 = x - 2 - x - 4
<=> -11x - 39 = - 6
<=> -11x = 33
<=> x = -3
Vậy x = -3 là nghiệm phương trình
\(a,10x-5-32+12x=7\)
\(22x=44\)
\(x=2\)
\(b,14x-35-35x+10+10x-14=x-2-x-4\)
\(-11x-39=-6\)
\(-11x=-33\)
\(x=3\)
sửa lại đoạn cuối
\(-11x=33\)
\(x=-3\)
Tìm x biết:
a)(2x-3)-(x-5)=(x+7)-(x+2)
b)(7x-5)-(6x+4)+(2x+3)-(2x+1)
c)(9x-3)-(8x+5)=(3x+2)
d)(x+7)-(2x+3)=(3x+5)-(2x+4)
a) ( 2x - 3 ) - ( x - 5 ) = ( x + 7 ) - ( x + 2 )
<=> 2x - 3 - x + 5 = x + 7 - x - 2
<=> x = 3
b)(7x-5)-(6x+4)=(2x+3)-(2x+1)
<=> 7x - 5 - 6x - 4 = 2x + 3 - 2x - 1
<=> x = 11
c)(9x-3)-(8x+5)=(3x+2)
<=> 9x - 3 - 8x - 5 = 3x + 2
<=> -2x = 10
<=> x = -5
d)(x+7)-(2x+3)=(3x+5)-(2x+4)
<=> x + 7 - 2x - 3 = 3x + 5 - 2x - 4
<=> -2x = -3
<=> x = 3/2
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,Tìm x, biết:
a, 3|x+4| - |2x+1| = 5
b, |x+5| - 3|2x+5| = 8
c,3|2x-3| - 6|x-1| = 3