\(3^{x+3}\cdot2=5^3+37\cdot1^{2015}\\\Rightarrow3^{x+3}\cdot2=125+37\\\Rightarrow3^{x+3}\cdot2=162\\\Rightarrow3^{x+3}=162:2\\\Rightarrow3^{x+3}=81\\\Rightarrow3^{x+3}=3^4\\\Rightarrow x+3=4\\\Rightarrow x=4-3\\\Rightarrow x=1\)

\(3^{x+3}.2=5^3+37.1^{2015}\\ 3^{x+3}.2=125+37.1=125+37=162\\ 3^{x+3}=\dfrac{162}{2}=81=3^4\\ Nên:x+3=4\\ Vậy:x=4-3=1\)

3^\(x+3\).2 = 5³ + 37.1²⁰¹⁵

3^\(x\).27.2 = 125 + 37

3\(^x\).54 = 162

3\(^x\)       = 162 : 54

3\(^x\)      = 3

\(x\)        = 1 

\(A=\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+...+\frac{1}{55\cdot57}\)

\(2A=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{55}-\frac{1}{57}\)

\(2A=\frac{1}{3}-\frac{1}{57}\)

\(2A=\frac{6}{19}\)

\(A=\frac{3}{19}\)

Ta có:

A=1/15+1/35+1/63+1/99+...+1/2015+1/3135

   =1/3.5+1/5.7+1/7.9+1/9.11+...+1/45.47+1/47.49

   =1/3-1/5+1/5-1/7+1/7-1/9+...+1/45-1/47+1/47-1/49

   =1/3-1/49

   =49/147-3/147

   =47/147

\(A=\frac{1}{12}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}+...+\frac{1}{2015}+\frac{1}{3135}\)

\(A=\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+\frac{1}{7\cdot9}+\frac{1}{9\cdot11}+...+\frac{1}{45\cdot47}+\frac{1}{47\cdot49}\)

\(A=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{47}-\frac{1}{49}\)

\(A=\frac{1}{3}-\frac{1}{49}\)

\(A=\frac{46}{147}\)

                             \(49-3=46\text{ nha bạn !}\)

a.\(\dfrac{9}{14}:x=\dfrac{3}{7}\)

\(x=\dfrac{9}{14}:\dfrac{3}{7}\)

\(x=\dfrac{3}{2}\)

b.\(\dfrac{7}{15}\times x=\dfrac{7}{10}\)

\(x=\dfrac{7}{10}:\dfrac{7}{15}\)

\(x=\dfrac{3}{2}\)

a: x=9/14:3/7=9/14x7/3=63/42=3/2

b: x=7/10:7/15=15/10=3/2

a,x=9/14:3/7

x=9/14.7/3

x=3/2

b,x=7/10:7/15

x=7/10.15/7

x=3/2

ừm khó phết mặc dù mình là học sinh lớp  6

để nghĩ cái

à ừ......................

lúc nào bùi đức thắng cx nói câu đấy nghe phát ngán

Có (x-1) + (x-2) + ...+ (x-99) = 99x - 1

<=> x-1 + x-2 + ... + x-99 = 99x - 1

       (x + x + ... + x) - (1+2+...+99) = 99x - 1

       99x - 4950 = 99x - 1 (loại)

Vậy x thuộc tập hợp rỗng