a) \(3\times x\times5=3,45\)
\(\Rightarrow\left(3\times5\right)\times x=3,45\)
\(\Rightarrow15\times x=3,45\)
\(\Rightarrow x=3,45:15\)
\(\Rightarrow x=0,23\)

\(a,3\times x\times5=3,45\\ 15\times x=3,45\\ x=0,23\)

a/ => x.9,9 + x . 1/10 = 20,06

=> x(9,9 + 1/10) = 20,06

=> x  = 2,006

b/ => x.100,01 - x.1/100 = 35,5

=> x(100,01 - 1/100) = 35,5

=> x = 0,355

\(x\times9,9+x:10=20,06\\ \Rightarrow x\times9,9+x\times0,1=20,06\\ \Rightarrow x\times\left(9,9+0,1\right)=20,06\\ \Rightarrow x\times10=20,06\\ \Rightarrow x=20,06:10\\ \Rightarrow x=2,006\)

X x 9,9 + X : 10 = 20,06

X x 9,9 + X x 1/10 = 20,06

X x  9,9 + X x 0,1  = 20,06

X x ( 9,9 + 0,1 ) = 20,06

X x 10 = 20,06

X = 20,06 : 10

X = 2,006

X x9,9 +X x 0,1=20,06

X x (9,9+0,1)=20,06

X x 10=20,06 

X=20,06:10

X=2,006

**** mk nha

x=2,006

dung k mk nha

X x 9,9 + X : 10 =  20,06

Xx 9,9 + X x 1/10 20,06

Xx 9,9 + X 0,1 = 20,06

X x 10 = 20 ,06

X= 20,06 x 10

X =2,006

x=2,006

X = 2,006

9,9 + x : 10 = 20,06

x : 10 = 20,06 - 9,9

x : 10 = 10,16

x = 10,16 x 10

x = 101,6