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a, x . 9,9 + x : 10 = 12,5
\(x.\frac{99}{10}+x.\frac{1}{10}=\frac{25}{2}\)
\(x\left(\frac{99}{10}+\frac{1}{10}\right)=\frac{25}{2}\)
\(x.10=\frac{25}{2}\)
\(x=\frac{25}{2}:10=\frac{25}{2}.\frac{1}{10}=\frac{5}{4}\)
b, \(x:\frac{1}{4}-x=\frac{78}{5}\)
\(x.4-x=\frac{78}{5}\)
\(x\left(4-1\right)=\frac{78}{5}\)
\(x.3=\frac{78}{5}\)
\(x=\frac{78}{5}:3=\frac{78}{5}.\frac{1}{3}=\frac{26}{5}\)
c, \(x:\frac{1}{10}-x:4-x.\frac{3}{4}=\frac{9}{4}\)
\(=x.10-x.\frac{1}{4}-x.\frac{3}{4}=\frac{9}{4}\)
\(x\left(10-\frac{1}{4}-\frac{3}{4}\right)=\frac{9}{4}\)
\(x.9=\frac{9}{4}\)
\(x=\frac{9}{4}:9=\frac{9}{4}.\frac{1}{9}=\frac{1}{4}\)
****
a: =5,67x(2,5x0,4)=5,67
b: =1,47(36+64)=1,47x100=147
c: =(0,25x40)x0,68=0,68
d: =25,8(1,02-1,01)=25,8x0,01=0,258
e: =0,7x(0,25x4)=0,7
g: =5,6(4+3+2+1)=5,6x10=56
h: =(2,5x4)x(12,5x0,8)=10x10=100
m: =7,89(54-53-1)=0
X : 0,25 - X = 15,6
X × 4 - X = 15,6
X × (4 - 1) = 15,6
X × 3 = 15,6
X = 15,6 : 3
X = 5,2
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X : 0,1 - X : 4 - X × 3/4 = 2,25
X × 10 - X × 1/4 - X × 3/4 = 2,25
X × (10 - 1/4 - 3/4) = 2,25
X × 9 = 2,25
X = 2,25 : 9
X = 0,25
a; y \(\times\) 9,1 + y \(\times\) 9,1 = 26,4
y \(\times\) (9,1 + 9,1) = 26,4
y \(\times\) 18,2 = 26,4
y = 26,4 : 18,2
y = 2
b; y \(\times\) 9,9 + y : 10 = 12,5
y \(\times\) 9,9 + y \(\times\) 0,1 = 12,5
y \(\times\) (9,9 + 0,1) = 12,5
y \(\times\) 10 = 12,5
y = 12,5 : 10
y = 1,25
a. ( 48 x 0,75 - 240 : 10 ) - ( 16 x 0,5 - 16 : 4 )
=(36-24)-(8-4)
=12-4
=8
b. (1000 x 0,1 - 900 x 0,1 - 90 x 0,1 ) x ( 142 x 0,5 - 240 x 0,25 )
=(100-90)x(71-60)
=10x11
=110
# mui #
a , x : 0,25 - x =15,6
x x 4 - x = 15,6
x x ( 4-1) = 15,6
x x 3 = 15,6
x = 15,6: 3
x = 5,2
Mấy con kia làm tương tự như con a
**** nhe
a: =472x2+472x5+472x2=472x9=4248
b: =28,8+28,8-14,4=43,2
c: =2,4(6,2+3,8)=24
a) \(210:x=2,1:0,25=8,4\)
\(x=210:8,4=25\)
b) \(x.2+x.0,5=6,25\)
\(2,5x=6,25\)
\(x=6,25:2,5=2,5\)
c) \(x:0,25-x=15,6\)
\(3x=15,6\)
\(x=5,2\)
d) \(x:12,5=3,75.4=15\)
\(x=15.12,5=187,5\)
e) \(x.12,6-x.5,6=42\)
\(7x=42\)
\(x=6\)
g) \(x:0,1-x:4-x.0,75=2,25\)
\(10x-\dfrac{x}{4}-\dfrac{3x}{4}=2,25\)
\(9x=2,25\)
\(x=0,25\)
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