đề bài là j bạn?? 

so sánh à bạn 

là tính tổng á

mình cần gấp

a) 5 + 45(2x - 1) = 10

45(2x - 1) = 10 - 5

45(2x - 1) = 5

2x - 1 = 5 : 45

2x - 1 = 1/9

2x = 1/9 + 1

2x = 10/9

x = 10/9 : 2

x = 5/9

b) 54 : (2ˣ⁻³ + 1) + 3 = 9

54 : (2ˣ⁻³ + 1) = 9 - 3

54 : (2ˣ⁻³ + 1) = 6

2ˣ⁻³ + 1 = 54 : 6

2ˣ⁻³ + 1 = 9

2ˣ⁻³ = 9 - 1

2ˣ⁻³ = 8

2ˣ⁻³ = 2³

x - 3 = 3

x = 3 + 3

x = 6

c) 14 + 36 : 3ˣ⁻⁵ = 18

36 : 3ˣ⁻⁵ = 18 - 14

36 : 3ˣ⁻⁵ = 4

3ˣ⁻⁵ = 36 : 4

3ˣ⁻⁵ = 9

3ˣ⁻⁵ = 3²

x - 5 = 2

x = 2 + 5

x = 7

a: =>45(2x-1)=5

=>2x-1=1/9

=>2x=10/9

=>x=5/9

b: =>\(\dfrac{54}{2^{x-3}+1}=6\)

=>\(2^{x-3}+1=9\)

=>\(2^{x-3}=8\)

=>x-3=3

=>x=6

c: \(14+36:3^{x-5}=18\)

=>\(\dfrac{36}{3^{x-5}}=18-14=4\)

=>\(3^{x-5}=9\)

=>x-5=2

=>x=7

\(a)5\frac{3}{5}+1\frac{3}{4}+4\frac{1}{4}+3\frac{2}{5}\)

\(=\)\((5\frac{3}{5}+3\frac{2}{5})+(1\frac{3}{4}+4\frac{1}{4})\)

\(=[8+(\frac{3}{5}+\frac{2}{5})]+[5+(\frac{3}{4}+\frac{1}{4})]\)

\(=(8+1)+(5+1)\)

\(=9+6=15\)

\(b)\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)

\(=(\frac{3}{4}+\frac{1}{4})+(\frac{18}{21}+\frac{3}{21})+(\frac{19}{32}+\frac{13}{32})\)

\(=1+1+1=3\)

_Học tốt_

a) 1/7 + 2/7 + 3/7 + 4/7 + 5/7 +6/7 = 3

b) 1/2 + 2/4 + 3/6 + 4/8 + 5/10 + 6/12 = 3

câu a bằng 3 nha
câu b cũng bằng 3 nha

a,\(\frac{1}{7}+\frac{2}{7}+\frac{3}{7}+\frac{4}{7}+\frac{5}{7}+\frac{6}{7}=\frac{1+2+3+4+5+6}{7}\)\(=\)\(\frac{21}{7}\)

b,\(\frac{1}{2}+\frac{2}{4}+\frac{3}{6}+\frac{4}{8}+\frac{5}{10}+\frac{6}{12}\)\(=\)\(\frac{1}{2}+\frac{1}{2}+\frac{1}{2}+\frac{1}{2}+\frac{1}{2}+\frac{1}{2}\)\(=\)\(\frac{1+1+1+1+1+1}{2}\)\(=\)\(\frac{6}{2}=6\div2=3\)

địt con mẹ mày lên

\(\dfrac{1}{3}\)-\(\dfrac{2}{15}\)+\(\dfrac{14}{15}\)=\(\dfrac{3}{15}\)-\(\dfrac{2}{15}\)+\(\dfrac{14}{15}\)

=\(\dfrac{13}{15}\)

\(\dfrac{3}{5}\)+4-\(\dfrac{6}{7}\)=\(\dfrac{3}{5}\)+\(\dfrac{20}{5}\)-\(\dfrac{6}{7}\)=\(\dfrac{23}{5}\)-\(\dfrac{6}{7}\)=\(\dfrac{161}{35}\)-\(\dfrac{30}{35}\)=\(\dfrac{131}{35}\)