Hãy tìm x, y biết:
a) 2,5: 4x=0,5: 0,2
b) 1/5. x :3 = 2/3:0,25
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a) \(2,5:0,4x=0,5:0,2\)
\(\Rightarrow\frac{5}{2}:4x=\frac{1}{2}:\frac{1}{5}=\frac{5}{2}\)
\(\Rightarrow4x=\frac{5}{2}:\frac{5}{2}=1\)
\(\Rightarrow x=\frac{1}{4}\)
b) \(\frac{1}{5}x:3=\frac{2}{3}:0,25\)
\(\Rightarrow\frac{1}{5}x:3=\frac{8}{3}\)
\(\Rightarrow\frac{1}{5}x=\frac{8}{3}.3=8\Rightarrow x=40\)
a)2,5:4x=0,5:0,2
2,5:4x=2.5
4x=2,5:2,5
4x=1
x=1:4
x=0,25
a, \(2,5:4x=0,5:0,2\)
\(\Rightarrow4x=\dfrac{2,5.0,2}{0,5}\)
\(\Rightarrow4x=1\Rightarrow x=\dfrac{1}{4}\)
b, \(\dfrac{1}{5}x:3=\dfrac{2}{3}:0,5\)
\(\Rightarrow\dfrac{1}{5}x=\dfrac{3.\dfrac{2}{3}}{0,5}\)
\(\Rightarrow\dfrac{1}{5}x=4\Rightarrow x=20\)
c, \(1,25:0,8=\dfrac{3}{8}:0,2x\)
\(\Rightarrow0,2x=\dfrac{0,8.\dfrac{3}{8}}{1,25}\)
\(\Rightarrow0,2x=0,24\Rightarrow x=1,2\)
Chúc bạn học tốt!!
a, \(2,5:4x=0,5:0,2\)
\(2,5:4x=2,5\)
\(4x=2,5:2,5\)
\(4x=1\)
\(x=1:4\)
\(x=\dfrac{1}{4}\)
Vậy .............
b, \(\dfrac{1}{5}x:3=\dfrac{2}{3}\)
\(\dfrac{1}{5}x=\dfrac{2}{3}.3\)
\(\dfrac{1}{5}x=2\)
\(x=2:\dfrac{1}{5}\)
\(x=10\)
Vậy .....
c, \(1,25:0,8=\dfrac{3}{8}:0,2x\)
\(1,5625=\dfrac{3}{8}:0,2x\)
\(0,2x=\dfrac{3}{8}:1,5625\)
\(0,2x=0,24\)
\(x=0,24:0,2\)
\(x=1,2\)
Vậy ...
2.a)\(\dfrac{3\text{x}-2}{2}\)=\(\dfrac{1-2\text{x}}{3}\)
<=>\(\dfrac{9\text{x}-6}{6}\)=\(\dfrac{2-4\text{x}}{6}\)
<=>9x-6=2-4x
<=>9x+4x=2+6
<=>13x=8
<=>x=\(\dfrac{8}{13}\)
1.a)2(x-0,5)+3=0,25(4x-1)
<=>2x-1+3=x-1phần4
<=>2x-x=-1/4+1-3
<=>x=-3/4
\(1,\\ a,A=4x^2\left(-3x^2+1\right)+6x^2\left(2x^2-1\right)+x^2\\ A=-12x^4+4x^2+12x^2-6x^2+x^2=-x^2=-\left(-1\right)^2=-1\\ b,B=x^2\left(-2y^3-2y^2+1\right)-2y^2\left(x^2y+x^2\right)\\ B=-2x^2y^3-2x^2y^2+x^2-2x^2y^3-2x^2y^2\\ B=-4x^2y^3-4x^2y^2+x^2\\ B=-4\left(0,5\right)^2\left(-\dfrac{1}{2}\right)^3-4\left(0,5\right)^2\left(-\dfrac{1}{2}\right)^2+\left(0,5\right)^2\\ B=\dfrac{1}{8}-\dfrac{1}{4}+\dfrac{1}{4}=\dfrac{1}{8}\)
\(2,\\ a,\Leftrightarrow10x-16-12x+15=12x-16+11\\ \Leftrightarrow-14x=-4\\ \Leftrightarrow x=\dfrac{2}{7}\\ b,\Leftrightarrow12x^2-4x^3+3x^3-12x^2=8\\ \Leftrightarrow-x^3=8=-2^3\\ \Leftrightarrow x=2\\ c,\Leftrightarrow4x^2\left(4x-2\right)-x^3+8x^2=15\\ \Leftrightarrow16x^3-8x^2-x^3+8x^2=15\\ \Leftrightarrow15x^3=15\\ \Leftrightarrow x^3=1\Leftrightarrow x=1\)
a ) y : 0.5 + y x 3 = 2,3
y x 2 + y x 3 = 2,3
y x ( 2 + 3 ) = 2,3
y x 5 = 2,3
y =0,46
b ) y : 0 , 25 - y : 2,5 = 0,18
y x 4 - y x \(\frac{2}{5}\) = 0,18
y x ( 4 - \(\frac{2}{5}\)) = 0 , 18
y x 3,6 = 0 , 18
y =0,05
\(a,\Leftrightarrow4x^2-20x-4x^2+7x-3=23\\ \Leftrightarrow-13x=-26\\ \Leftrightarrow x=2\\ b,\Leftrightarrow x^2+4x+4+4x^2-12x+9=5x^2+35x\\ \Leftrightarrow-43x=-13\\ \Leftrightarrow x=\dfrac{13}{43}\)
a) \(4x\left(x-5\right)-\left(x-1\right)\left(4x-3\right)=23\)
\(\Leftrightarrow4x^2-20x-4x^2+7x-3=23\)
\(\Leftrightarrow13x=-26\Leftrightarrow x=-2\)
b) \(\left(x+2\right)^2+\left(2x-3\right)^2=5x\left(x+7\right)\)
\(\Leftrightarrow x^2+4x+4+4x^2-12x+9=5x^2+35x\)
\(\Leftrightarrow43x=13\Leftrightarrow x=\dfrac{13}{43}\)
a: \(\Leftrightarrow2x+\dfrac{7}{2}=\dfrac{16}{3}:\dfrac{11}{3}=\dfrac{16}{11}\)
=>2x=-45/22
hay x=-45/44
b: =>x/7=-1/28:1/4=-1/7
=>x=-1
a)(7/2+2x).11/3=16/3
7/2+2x=16/3:11/3
7/2+2x=16/3.3/11
7/2+2x=16/11
2x=16/11-7/2
2x= -45/22
x= -45/22:2
x= -45/44
Vậy x= -45/44
b)x/7 +1/4= -1/28
x/7= -1/28-1/4
x/7= -2/7
=>x= -2
a) \(2,5:4x=0,5:0,2\)
\(2,5:4x=\frac{5}{2}\)
\(4x=2,5:\frac{5}{2}\)
\(4x=1\)
\(x=\frac{1}{4}\)
Vậy \(x=\frac{1}{4}\)
b) \(\frac{1}{5}.x:3=\frac{2}{3}:0,25\)
\(\frac{1}{5}.x:3=\frac{8}{3}\)
\(\frac{1}{5}.x=\frac{8}{3}.3\)
\(\frac{1}{5}.x=8\)
\(x=8:\frac{1}{5}\)
\(x=40\)
Vậy \(x=40\)
a) \(\frac{2,5}{4x}=\frac{0,5}{0,2}\)
\(=>4x=\frac{0,2.2,5}{0,5}=1\)
\(=>x=\frac{1}{4}\)
b) \(\frac{1}{5}.\frac{x}{3}=\frac{2}{3}:0,25\)
\(=>\frac{x}{15}=\frac{4}{3}\)
\(=>x=\frac{4.15}{3}=20\)