Question

[ban binh duong]

Câu 1 tính hợp lí

a,A=\(\frac{-9}{11}.\frac{3}{8}-\frac{9}{11}.\frac{5}{8}+\frac{17}{11}\)

b,B=\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{53.55}\)

Câu2 tìm x

a,\(x+5-\frac{1}{2}=3\frac{1}{2}\)

b,\(3^{x+1}=27\)

c,\(2016.\left[25-\left(3x+2\right)\right]=3^2.7\)

d,\(\frac{x}{6}+\frac{x}{10}+\frac{x}{15}+\frac{x}{21}+\frac{x}{28}+\frac{x}{36}+\frac{x}{45}+\frac{x}{60}+\frac{x}{78}=\frac{220}{39}\)

Ai giải nhanh tớ tick cho

Thank you

Answer 1

[Nguyễn Thị Thu Huyền]

\(-\frac{9}{11}\cdot\frac{3}{8}-\frac{9}{11}\cdot\frac{5}{8}+\frac{17}{11}=-\frac{9}{11}\left(\frac{3}{8}+\frac{5}{8}\right)+\frac{17}{11}=-\frac{9}{11}\cdot1+\frac{17}{11}=1\)

\(\frac{2}{1.3}+....+\frac{2}{53.55}=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{53}-\frac{1}{55}=1-\frac{1}{55}=\frac{54}{55}\)

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

\(x+5=3.5+0.5=4\)

\(x=4-5=-1\)

\(3^{x+1}=27=3^3\)

\(x+1=3\)

vậy x=2

Answer 2

[Nguyễn Thị Thu Huyền]

bây h bn mún tớ iair hộ bn trừ câu cuối ko