A, 11/12

B, 12,6

a,

x- 7/12 = 1/3

x = 1/3 + 7/12

x = 11/12

b,

x + 31/10 = 14,5

x = 14,5 - 31/10

x = 57/5

\(a,\\ x=\dfrac{1}{3}+\dfrac{7}{12}=\dfrac{11}{12}\\ b,\\ x+\dfrac{31}{10}=\dfrac{157}{10}\\ x=\dfrac{157}{10}-\dfrac{31}{10}=\dfrac{63}{5}\)

\(x+\frac{31}{10}=x+\frac{12}{10}+\frac{19}{10}=14,5+\frac{12}{10}\)

\(x+\frac{19}{10}=14,5\)

\(x+1,9=14,5\)

\(x=14,5-1,9=12,6\)

x+\(\frac{31}{10}\)=\(\frac{157}{10}\)

x=\(\frac{157}{10}-\frac{31}{10}\)

x=\(\frac{63}{5}\)

\(\frac{63}{5}\)

x+3.1=15.7

x=12.6

tik nha

63/5 duyệt đi

a)Ta có :

x-8,7=5 x 1,2 = 6

=> x = 6+8,7 = 14,7

Vậy x=14,7

b) Ta có 

x+31/10=14,5+12/10=15,7

=> x=15,7-31/10=12,6.

Vậy x=12,6

a) ( x - 8,7 ) = 5 * 1,2

      x - 8,7   =     6

      x           =  6 + 8,7

      x           =     14,7

b) x + 31/10 = 14,5 +12/10

b) x=12,6

do mỏi tay ahihi

(30:15/2+0,5.3-1,5).(9/2-7/2):(14,5-x)=10

<=>(4+1,5-1,5).1:(14,5-x)=10

<=>4:(14,5-x)=10

<=>14,5-x=2/5

<=>x=14,1

 8 x 9 x 10 + 6 x 25 x 12 + 4 x 18 x 31 + 2 x 36 x 34

=72x10+72x25+72x31+72x34

=72x(10+25+31+34)

=72x100

=7200

  8 x 9 x 10 + 6 x 25 x 12 + 4 x 18 x 31 + 2 x 36 x 34

=72 x 10 + 72 x 25 + 72 x 31 + 72 x 34

= 72 ( 10 + 25 + 31 + 34 )

= 72 x 100

= 7200

chứng minh Phương trình trên vô nghiệm

145 /10 =14.5

145/10=14,5

bằng nhau