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c)\(\dfrac{3}{8}\times\dfrac{5}{8}+y=\dfrac{5}{4}\)
\(\dfrac{15}{64}+y=\dfrac{5}{4}\)
\(y=\dfrac{5}{4}-\dfrac{15}{64}\)
\(y=\dfrac{65}{64}\)
d, \(\dfrac{3}{8}+\dfrac{5}{8}\times y=\dfrac{5}{4}\)
\(\dfrac{5}{8}\times y=\dfrac{5}{4}-\dfrac{3}{8}\)
\(\dfrac{5}{8}\times y=\dfrac{7}{8}\)
\(y=\dfrac{7}{8}:\dfrac{5}{8}\)
\(y=\dfrac{7}{5}\)
a, 3/4 x y = 3/5 + 3/10
3/4 x y = 9/10
y = 9/10 : 3/4
y = 6/5
b, 3/5 : y = 3/4 - 2/5
3/5 : y = 7/20
y = 3/5 : 7/20
y = 12/7
- Ta có: \(\frac{3}{x}+\frac{y}{3}=\frac{5}{6}\)
\(\Leftrightarrow\frac{3}{x}=\frac{5}{6}-\frac{y}{3}\)
\(\Leftrightarrow\frac{3}{x}=\frac{5-2y}{6}\)
\(\Leftrightarrow x.\left(5-2y\right)=18=1.18=\left(-1\right).\left(-18\right)=2.9=\left(-2\right).\left(-9\right)=3.6=\left(-3\right).\left(-6\right)\)
- Vì \(5-2y\)là lẻ \(\Rightarrow\)\(5-2y\in\left\{-9,-3,-1,1,3,9,\right\}\)
- Ta có bảng giá trị:
\(5-2y\) | \(-9\) | \(-3\) | \(-1\) | \(1\) | \(3\) | \(9\) |
\(x\) | \(-2\) | \(-6\) | \(-18\) | \(18\) | \(6\) | \(2\) |
\(y\) | \(7\) | \(4\) | \(3\) | \(2\) | \(1\) | \(-2\) |
\(\left(TM\right)\) | \(\left(TM\right)\) | \(\left(TM\right)\) | \(\left(L\right)\) | \(\left(L\right)\) | \(\left(L\right)\) |
Vậy \(\left(x,y\right)\in\left\{\left(-2,7\right);\left(-6,4\right);\left(-18,3\right)\right\}\)
!@#$!@$! ^_^ Chúc bn hok tốt ^_^ @#$!#$!
1.
( 10 - 9,34 ) + ( 10 - 9,66 )
= 0,66 + 0,34
= 1
12 - ( 12 - 9,36 )
= 12 - 2,64
= 9,36
38,52 + 0,302 x 100 - 0,72
= 38,52 + 30,2 - 0,72
= 68,72 - 0,72
= 68
2.
\(1-\left(5\frac{3}{8}+x-7\frac{5}{24}\right):16\frac{2}{3}=0\)
\(1-\left(\frac{43}{8}+x-\frac{173}{24}\right):\frac{50}{3}=0\)
\(\left(\frac{43}{8}+x-\frac{173}{24}\right):\frac{50}{3}=0+1=1\)
\(\left(x-\frac{151}{12}\right):\frac{50}{3}=1\)
\(x-\frac{151}{12}=1\times\frac{50}{3}\)
\(x-\frac{151}{12}=\frac{50}{3}\)
\(x=\frac{50}{3}+\frac{151}{12}\)
\(x=\frac{117}{4}\)
Bài 1
\(\left(10-9,34\right)+\left(10-9,66\right)\)
\(=0.66+0,34=1\)
\(12-\left(12-9,36\right)\)
\(=12-2.64=9,36\)
\(38,52+0,302.100-0,72\)
\(=38,52+30,2-0,72\)
\(=7.6\)
Bài 2
\(1-\left(5\frac{3}{8}+x-7\frac{5}{24}\right):16\frac{2}{3}=0\)
\(1-\left(\frac{43}{8}+x-\frac{173}{24}\right):\frac{50}{3}=0\)
\(\left(\frac{43}{8}+x-\frac{173}{24}\right):\frac{50}{3}=1\)
\(\frac{43}{8}+x-\frac{173}{24}=\frac{3}{50}\)
\(\frac{43}{8}+x=\frac{3}{50}+\frac{173}{24}\)
\(\frac{43}{8}+x=\frac{4361}{600}\)
\(x=\frac{142}{75}\)( gửi lại bài 2 đã )
\(a,5\frac{1}{4}+3,25-50\%+y=15,25\)
\(\Leftrightarrow5,25+3,25-\frac{50}{100}+y=15,25\)
\(\Leftrightarrow5,25+3,25-0,5+y=15,25\)
\(\Leftrightarrow8+y=15,25\)
\(\Leftrightarrow y=15,25-8=7,25\)
\(b,(y-3):2=2010\)
\(\Leftrightarrow y-3=4020\)
\(\Leftrightarrow y=4023\)
\(\frac{7}{4}-y.\frac{4}{3}=\frac{5}{19}\)
\(\Rightarrow y.\frac{4}{3}=\frac{7}{4}-\frac{5}{19}\)
\(\Rightarrow y.\frac{4}{3}=\frac{113}{76}\)
\(\Rightarrow y=\frac{113}{76}:\frac{4}{3}\)
\(\Rightarrow y=\frac{4}{3}.\frac{113}{76}\)
\(\Rightarrow y=\frac{113}{57}\)
vậy y= 113/57
b) y + y : 0,5 + y : 0,25 + y : 0,125 = 15
yx1+yx2+yx4+yx8=15
yx(1+3+4+8)=15
yx15=15
y=15:15
y=1
\(y+y.\frac{1}{3}.\frac{9}{2}+y.\frac{7}{2}=25\)
\(y+y.6+y.\frac{7}{2}=25\)
\(y.\left(1+6+\frac{7}{2}\right)=25\)
\(y.\frac{21}{2}=25\)
\(y=25:\frac{21}{2}\)
\(y=25.\frac{2}{21}\)
\(y=\frac{50}{21}\)
\(y.5+y.3+y+y=50\)
\(y.\left(5+3+1+1\right)=50\)
\(y.10=50\)
\(y=5\)
Ta có \(2x-8=0\Rightarrow x=4\)
\(y-3=0\Rightarrow y=3\)
Vậy \(x=4;y=3\)