1.Tìm x
a, x ː 2,2 = (28,7 - 13,5 ). 2
b, (3 3/4 . x +75%) ː 2/3 = -1
c, 4x - ( 3 + 5x ) = 14
tìm x
a) x : 2,2 = (28,7 -13,5) . 2
b) 216,4 : x = (5,24 + 4,76) : 2
a, x : 2,2 = (28,7 -13,5) . 2
x : 2,2 = 30,4
x =30,4 x 2,2
x =66,88
b, 216,4 : x = (5,24 + 4,76) : 2
<=> 216,4 : x = 5
<=> x = 216,4 : 5 =43,28
\(a,x:2,2=\left(28,7-13,5\right).2\)
\(x:2,2=15,2.2\)
\(x:2,2=30,4\)
\(x=30,4.2,2\)
\(x=66,88\)
\(b,216,4:x=\left(5,24+4,76\right):2\)
\(216,4:x=10:2\)
\(216,4:x=5\)
\(x=216,4:5\)
\(x=43,28\)
x :2,2 = 15,2 . 2
x : 2,2 =30,4
x = 2,2 . 30 , 4
x= 66,88
a, 9/25 ː 1 =
b1,12 . -9/8 = b2, 12 ː -9/8 =
c1, 3 . -5/6 = c2, 3 ː -5/6 =
tìm x
a) 4(18-5x)-12(3x-7)=15(2x-16)-6(x+14)
b) 5(3x+5)-4(2x-3)=5x+3(2x+12)+1
c) 2(5x-8)-3(4x-5)=4(3x-4)+11
a) \(\Rightarrow72-20x-36x+84=30x-240-6x-84\)
\(\Rightarrow80x=480\Rightarrow x=6\)
b) \(\Rightarrow15x+25-8x+12=5x+6x+36+1\)
\(\Rightarrow4x=0\Rightarrow x=0\)
c) \(\Rightarrow10x-16-12x+15=12x-16+11\)
\(\Rightarrow14x=4\Rightarrow x=\dfrac{2}{7}\)
a \(\dfrac{x}{y}\) - \(\dfrac{3}{8}\) = \(1\dfrac{1}{2}\) b \(\dfrac{4}{9}\) ː \(\dfrac{x}{y}\) = \(1\dfrac{1}{2}\)
giup mik với mik cần gấp
450 ː [41 - (2x -5)] = 3 mũ 2 x 5
450 : [ 41 - ( 2x - 5 )] = 32 . 5
450 : [ 41 - ( 2x - 5 )] = 9 . 5
450 : [ 41 - ( 2x - 5 )] = 45
41 - ( 2x - 5) = 450 : 45
41 - ( 2x - 5 ) = 10
2x - 5 = 41 - 10
2x - 5 = 31
2x = 31 + 5
2x = 36
x = 36 : 2
x = 18
Vậy x = 18
Học tốt!!!
\(450:\left[41-\left(2x-5\right)\right]3^{2.5}\)
450 : [41 - 2x + 5] = 9 . 5
450 : [46 - 2x] = 45
46 - 2x = 10
2x = 36
x = 18
Bài1 tính:
a)\(\dfrac{2}{5}\)+\(\dfrac{5}{12}\); b)\(\dfrac{2}{3}\) - \(\dfrac{3}{8}\); c)\(\dfrac{3}{7}\) ✖ \(\dfrac{4}{9}\); d) \(\dfrac{11}{10}\) - \(\dfrac{2}{5}\) ː \(\dfrac{2}{3}\)
2/5+5/12
=49/60
2/3-3/8
=7/24
3/7.4/9
=4/21
11/10-2/5:2/3
=11/10-3/5
=1/2
tim x
a) (5x-3)^2-(4x-7)^2
b) (2x+7)^2=9(x+2)^2
c) (x+2)^2=9(x^2-4x+4)
b: Ta có: \(\left(2x+7\right)^2=9\left(x+2\right)^2\)
\(\Leftrightarrow\left(3x+4-2x-7\right)\left(3x+4+2x+7\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(5x+11\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{11}{5}\end{matrix}\right.\)
c: ta có: \(\left(x+2\right)^2=9\left(x^2-4x+4\right)\)
\(\Leftrightarrow\left(3x-6\right)^2-\left(x+2\right)^2=0\)
\(\Leftrightarrow\left(3x-6-x-2\right)\left(3x-6+x+2\right)=0\)
\(\Leftrightarrow\left(2x-8\right)\left(4x-4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=1\end{matrix}\right.\)
Tìm x
a) -x/27 -1 = 2/3
b) x - 4 = -14/35 : 20/-21
c) x + 2/3 = -1/12 . -4/5
d) 1/5 - 3/5x = -15/14 :20/-21
e) -3/7x = 3/5 . 28/9
f)1/2x + 3/5x = -2/3
a: =>x/27+1=-2/3
=>x/27=-5/3
=>x=-45
b: \(\Leftrightarrow x-4=\dfrac{2}{5}:\dfrac{20}{21}=\dfrac{2}{5}\cdot\dfrac{21}{20}=\dfrac{42}{100}=\dfrac{21}{50}\)
=>x=221/50
c: \(\Leftrightarrow x+\dfrac{2}{3}=\dfrac{4}{60}=\dfrac{1}{15}\)
=>x=1/15-2/3=1/15-10/15=-9/15=-3/5
d: \(\Leftrightarrow x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{15}{14}\cdot\dfrac{21}{20}\)
=>\(x\cdot\dfrac{3}{5}=\dfrac{1}{5}-\dfrac{3}{2}\cdot\dfrac{3}{4}=\dfrac{1}{5}-\dfrac{9}{8}=\dfrac{-37}{40}\)
=>x=-37/24
e: =>-3/7x=84/45
=>x=-196/45
f: =>11/10x=-2/3
=>x=-20/33
Tìm x
(4x+3)2+(3x-4)2+(2+5x)(2-5x)=x
Thu gọn biểu thức
a)(x-3)(x+3)-(x-3)2
b)(3x-1)2+2(3x-1)(2x+1)+(2x+1)2
giúp mình với ;-;
1) \(\Rightarrow16x^2+24x+9+9x^2-24x+16+4-25x^2=x\)
\(\Rightarrow x=29\)
2)
a) \(=x^2-9-x^2+6x-9=6x-18\)
b) \(=\left(3x-1+2x+1\right)^2=\left(5x\right)^2=25x^2\)