(4x - 9). (2,5 - 7/2 . x) = 0
( 4x - 9 ) . ( 2,5 + -7/3 . x ) = 0
Ta có: ( 4x - 9 ) . ( 2,5 + -7/3 . x ) = 0
<=> 4x - 9 = 0
2,5 + -7/3 . x = 0
<=> 4x = 9
-7/3.x = -2,5
<=> x = 9 : 4
x = -2,5 : -7/3
<=> x = 9/4
x = 6/35
\(\left(4x-9\right).\left(2,5+\dfrac{-7}{3}.x\right)=0\)
=>4x-9=0 hoặc 5/2-7/3x=0
=>x=9/4 hoặc x=15/14
\(\left(4x-9\right).\left(2,5+\dfrac{-7}{3}.x\right)=0\)
\(=>\left[{}\begin{matrix}4x-9=0\\2,5+\dfrac{-7}{3}.x=0\end{matrix}\right.=>\left[{}\begin{matrix}x=\dfrac{9}{4}\\x=\dfrac{15}{14}\end{matrix}\right.\)
=> \(\left(4x-9\right).\left(\dfrac{5}{2}+\dfrac{-7}{3}.x\right)=0\)
=> \(\left[{}\begin{matrix}4x-9=0\\\dfrac{5}{2}+\dfrac{-7}{3}.x=0\end{matrix}\right.=>\left[{}\begin{matrix}4x=9=>x=\dfrac{9}{4}\\\dfrac{-7}{3}.x=\dfrac{-5}{2}=>x=\dfrac{15}{14}\end{matrix}\right.\)
Tìm x :
1) \(\left(-0,75x+\dfrac{5}{2}\right).\dfrac{4}{7}-\left(-\dfrac{1}{3}\right)=-\dfrac{5}{6}\)
2) \(\left(4x-9\right)\left(2,5+\dfrac{-7}{3}x\right)=0\)
3) \(\left|x-\dfrac{3}{4}\right|-\dfrac{1}{2}=0\)
4)\(\left(\dfrac{3}{5}-\dfrac{2}{3}x\right)^3=\dfrac{-64}{125}\)
3: \(\left|x-\dfrac{3}{4}\right|-\dfrac{1}{2}=0\)
\(\Leftrightarrow\left|x-\dfrac{3}{4}\right|=\dfrac{1}{2}\)
\(\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{3}{4}=\dfrac{1}{2}\\x-\dfrac{3}{4}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{4}\\x=\dfrac{1}{4}\end{matrix}\right.\)
a) (5x-1) . ( 2x-1/3)=0
b) ( -0,6x-1/2) .3/4-(-1)=1/3
c) ( 4x-9) ( 2,5+-7/3x)=0
d) 1/4x-1+1/3.(5/2x-6)-( 3/8x +)=4,5
\(\left(5x-1\right)\left(\frac{2x-1}{3}\right)=0\)
\(\Leftrightarrow\left(\frac{\left(5x-1\right)\left(2x-1\right)}{3}\right)=0\)
\(\Leftrightarrow\left(5x-1\right)\left(2x-1\right)=0\)
\(\Rightarrow\orbr{\begin{cases}5x-1=0\\2x-1=0\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=\frac{1}{5}\\x=\frac{1}{2}\end{cases}}\)
Vậy \(x=\frac{1}{5}\)hoặc\(x=\frac{1}{2}\)
b) \(\left(-0,6x-\frac{1}{2}\right).\frac{3}{4}-\left(-1\right)=\frac{1}{3}\)
\(\Leftrightarrow\left(-0,6x-\frac{1}{2}\right).\frac{3}{4}=\frac{-2}{3}\)
\(\Leftrightarrow\left(-0,6x-\frac{1}{2}\right)=\frac{-8}{9}\)
\(\Leftrightarrow-0,6x=\frac{-7}{18}\)
\(\Rightarrow x=\frac{35}{54}\)
7/8 x-1/4x=9/16
x:14/5=-2,5
\(\frac{7}{8}x-\frac{1}{4}x=\frac{9}{16}\)
\(\Rightarrow\left(\frac{7}{8}-\frac{1}{4}\right)x=\frac{9}{16}\)
\(\Rightarrow\left(\frac{7}{8}-\frac{2}{8}\right)x=\frac{9}{16}\)
\(\Rightarrow\frac{5}{8}x=\frac{9}{16}\)
\(\Rightarrow x=\frac{9}{16}:\frac{5}{8}\)
\(\Rightarrow x=\frac{9}{16}.\frac{8}{5}\)
\(\Rightarrow x=\frac{9}{10}\)
\(x:\frac{14}{5}=-2,5\)
\(\Rightarrow x:\frac{14}{5}=-\frac{5}{2}\)
\(\Rightarrow x=-\frac{5}{2}.\frac{14}{5}\)
\(\Rightarrow x=-7\)
Chúc bạn học tốt !!!
Ai giúp mik với
Ai làm đầu đúng mình tích
b,(5/2-3X)=25/9
c,-5/6X+0,75=15/4
d,12/7-|x-1/3|=3/2
e,(x-1)mũ 5=-32
f,2 mũ x-3.2 mũ x=-8
g,9 mũ 5/3 mũ x=(-3) mũ 2
h,1/2x+3/5x=-33/25
k,(4x-9)(2,5+-7/3x)=0
b) (5/2-3x)=25/9
3x = 5/2-25/9
3x =-5/18
x =-5/18:3
x=-5/54
\(e.\left(x-1\right)^5=-32\)
\(\left(x-1\right)^5=\left(-2\right)^5\)
\(x-1=-2\)
\(x\) \(=-2+1\)
\(x\) \(=-1\)
Vậy \(x=-1\)
A(2,3x-6,5)(0,1x+2)=0
B(2x+7)(x-5)(5x+1)=0
C(x-1)(2x+7)(x2+2)=0
D(4x-10)(24+5x)=0
E(3,5-7x)(0,1x+2,3)=0
F (5x+2)(x+7)=0
G15 (x+9)(x-3)(x+21)=0
H (x2+1)(×2-4x+4)=0
I(3x-2)(2 (x+3)/9-4x-3/5)=0
\(A.\left(2,3x-6,5\right)\left(0,1x+2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}2,3x-6,5=0\\0,1x+2=0\end{cases}\Leftrightarrow\orbr{\begin{cases}2,3x=6,5\\0,1x=-2\end{cases}}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{6,5}{2,3}\\x=-20\end{cases}}\)
Tìm x:
a) | 2x - 5 | + | 2,5 - x | = 0
b) | x - 1,5 | + | x + 3 | = 0
c) ( 5x - 2 )2 = 1
d) (4x - 1)3 + 7 = -20
a) làm mẫu cho cả phần b lun
\(|2x-5|+|2,5-x|=0\left(1\right)\)
Ta có: \(2x-5=0\Leftrightarrow x=\frac{5}{2}\)
\(2,5-x=0\Leftrightarrow x=2,5=\frac{5}{2}\)
Lập bảng xét dấu :
+) Với \(x< \frac{5}{2}\Rightarrow\hept{\begin{cases}2x-5< 0\\2,5-x< 0\end{cases}\Rightarrow}\hept{\begin{cases}|2x-5|=5-2x\\|2,5-x|=x-2,5\end{cases}}\left(2\right)\)
Thay (2) vào (1) ta được :
\(5-2x+x-2,5=0\)
\(-x+\frac{5}{2}=0\)
\(x=\frac{5}{2}\)( loại )
+) Với \(x\ge\frac{5}{2}\Rightarrow\hept{\begin{cases}2x-5\ge0\\2,5-x\ge0\end{cases}\Rightarrow}\hept{\begin{cases}|2x-5|=2x-5\\|2,5-x|=2,5-x\end{cases}}\left(3\right)\)
Thay (3) vào (1) ta được :
\(2x-5+2,5-x=0\)
\(x-\frac{5}{2}=0\)
\(x=\frac{5}{2}\)( chọn )
Vậy \(x=\frac{5}{2}\)
a) |2x - 5| + |2,5 - x| = 0
2x - 5 = 0 hoặc 2,5 - x = 0
2x = 0 + 5 -x = 0 - 2,5
2x = 5 -x = -2,5
x = 2,5 x = 2,5
=> x = 2,5
b) |x - 1,5| + |x + 3| = 0
x - 1,5 = 0 hoặc x + 3 = 0
x = 0 + 1,5 x = 0 - 3
x = 1,5 x = -3
=> x = 1,5 hoặc x = -3
c) (5x - 2)2 = 1
(5x - 2)2 = 12
5x - 2 = 1; -1
5x - 2 = 1 hoặc 5x - 2 = -1
5x = 1 + 2 5x = -1 + 2
5x = 3 5x = 1
x = 3/5 x = 1/5
=> x = 3/5 hoặc x = 1/5
d) (4x - 1)3 + 7 = -20
(4x - 1)3 = -20 - 7
(4x - 1)3 = -27
(4x - 1)3 = (-3)3
4x - 1 = -3
4x = -3 + 1
4x = -2
x = -2/4 = -1/2
a)Ta có : \(\left|2x-5\right|\ge0\forall x\)
\(\left|2,5-x\right|\ge0\)
\(\Rightarrow\left|2x-5\right|+\left|2,5-x\right|=0\Leftrightarrow\hept{\begin{cases}\left|2x-5\right|=0\\\left|2,5-x\right|=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}2x-5=0\\2,5-x=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}2x=5\\x=2,5\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=2,5\\x=2,5\end{cases}}\)
\(\Rightarrow x=2,5\)
b) Ta có : \(\left|x-1,5\right|\ge0\forall x\)
\(\left|x+3\right|\ge0\forall x\)
\(\Rightarrow\left|x-1,5\right|+\left|x+3\right|=0\Leftrightarrow\hept{\begin{cases}\left|x-1,5\right|=0\\\left|x+3\right|=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x-1,5=0\\x+3=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=1,5\\x=-3\end{cases}}\)
\(\Rightarrow x\in\varnothing\)
c) \(\left(5x-2\right)^2=1\)
\(\Rightarrow\left(5x-2\right)^2=1^2\)
\(\Rightarrow5x-2=\pm1\)
\(\Rightarrow\orbr{\begin{cases}5x-2=1\\5x-2=-1\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}5x=3\\5x=1\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=0,6\\x=0,2\end{cases}}\)
d) \(\left(4x-1\right)^3+7=-20\)
\(\Rightarrow\left(4x-1\right)^3=-27\)
\(\Rightarrow\left(4x-1\right)^3=\left(-3\right)^3\)
\(\Rightarrow4x-1=-3\)
\(\Rightarrow4x=-2\)
\(\Rightarrow x=-0,5\)
a, 6,5 - 9/4 :| x + 1/3 |= 2
b, 11/4 + 3/2: | 4x - 1/ 5|= 7/2
c, 15/4 - 2,5 :| 3/4x + 1/2|= 3
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