Giúp gì thế bạn?

\(\dfrac{1}{2}+\dfrac{13}{19}-\dfrac{4}{9}+\dfrac{6}{19}+\dfrac{5}{18}\)

\(=\left(\dfrac{1}{2}-\dfrac{4}{9}+\dfrac{5}{18}\right)+\left(\dfrac{13}{19}+\dfrac{6}{19}\right)\)

\(=\dfrac{9-8+5}{18}+1=\dfrac{1}{3}+1=\dfrac{4}{3}\)

mik dang gap giup mik vs

(2\(x\) - 3).(\(\dfrac{5}{4}\)\(x\) - 6)  = 0

\(\left[{}\begin{matrix}2x-3=0\\\dfrac{5}{4}x-6=0\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=6:\dfrac{5}{4}\end{matrix}\right.\)

\(\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{24}{5}\end{matrix}\right.\)

Vậy \(x\) \(\in\) {\(\dfrac{3}{2}\); \(\dfrac{24}{5}\)}

\(x-3=y\left(x+2\right)\)
\(x-3=xy+2y\)
\(x-xy+2y=3\)
\(x\left(1-y\right)-2+2y=1\)
\(x\left(1-y\right)-2\left(1-y\right)=1\)
\(\left(1-y\right)\left(x-2\right)=1\)
Lập bảng:

Vậy \(\left(x;y\right)\in\left\{\left(3;0\right);\left(1;2\right)\right\}\)

các cặp (x,y)=(-7,2);(-3,6);(-1,-4);(3,0)

1/3 + 13/19 - 4/9 + 6/19 + 5/18

= (13/19 + 6/19) - (1/3 + 4/9) + 5/18

= 1 - 7/9 + 5/18

= 1 - 14/18 + 5/18

= 13/18 + 5/18

= 1

Gọi d=ƯCLN(3n+1;4n+1)

=>\(\left\{{}\begin{matrix}3n+1⋮d\\4n+1⋮d\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}12n+4⋮d\\12n+3⋮d\end{matrix}\right.\)

=>\(12n+4-12n-3⋮d\)

=>\(1⋮d\)

=>d=1

=>ƯCLN(4n+1;3n+1)=1

=>\(\dfrac{3n+1}{4n+1}\) là phân số tối giản

ta có a>0

có a<1+1/1.2+.......+1/2020.2021

a<1/2021 <1

a<1

vậy 0<a<1

vạya không là số nguyên.

Giúp em với ạ

x=3

(1/2)^x=(1/2)^3

=> x+3

vẫy=3