7B=7+7^2+7^3+...+7^2022

7B-B=(7+7^2+7^3+...+7^2022)-(1 + 7 + 7² + ... + 7²⁰²¹)

6B=7^2022-1

B=(7^2022-1)/6

bằng 83/90

\(\frac{1}{2}+\frac{1}{5}+\frac{2}{9}\)

=\(\frac{45}{90}+\frac{18}{90}+\frac{20}{90}\)

=\(\frac{83}{90}\)

\(\frac{1}{2}+\frac{1}{5}+\frac{2}{9}=\frac{1}{2}_{\left(45\right)}+\frac{1}{5}_{\left(18\right)}+\frac{2}{9}_{10}\)

\(=\frac{45}{90}+\frac{18}{90}+\frac{20}{90}=\frac{45+18+20}{90}\)

\(=\frac{83}{90}\)

\(19\div\dfrac{2}{3}+43,5\times1\) 

\(=19\times\dfrac{3}{2}+43,5\)

\(=\dfrac{57}{2}+43,5\)

\(=28,5+43,5\)

\(=72\)

\(\dfrac{1}{2}+36,5\times150\%+1,5\)

\(=0,5+36,5\times1,5+1,5\)

\(=0,5+54,75+1,5\)

\(=55,25+1,5\)

\(=56,75\)

0,36 x 0,50 + 0,18 x 726 x 2 + 3 x 324 x 0,12

=0,36 x 0,50 +0,36x726+0,36x324

=0,36x(0,50+726+324)

=0,36x1050

=378,18

lấy máy tính mà bấm

tính nhanh bạn

9/14:6/7 +3/12:2*1/2

 =3/4+1/8:2*1/2

=3/4+1/16*1/2

=3/4+1/32

=25/32

\(\frac{9}{14}\): \(\frac{6}{7}\) + \(\frac{3}{12}\): \(2\)x\(\frac{1}{2}\)

= \(\frac{3}{4}\)\(+\)\(\frac{1}{8}\)x\(\frac{1}{2}\)

=\(\frac{3}{4}\)\(+\)\(\frac{1}{16}\)

=\(\frac{9}{16}\)\(+\)\(\frac{1}{16}\)

= \(\frac{10}{16}\)

=\(\frac{5}{8}\)

nhé

9/14 : 6/7 + 3/12 : 2 * 1/2 =13/16

a=8/7

b=22/9

c=73/126

a, 1-3/7+4/7

 = 1-7/7

 = 1-1

 = 0

b,3-7/9+2/9

 = 3- 9/9

 = 3- 1

 = 2

c,=73/126

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