ta có (x-1)(y+2)=5

do x,y nguyên nên x-1, y+2 nguyên

=> \(x-1,y+2\inƯ\left(5\right)\). Nên ta có bảng sau

vậy ......

bạn tự kết luận nhé

tk mk nha 

*****Chúc bạn học giỏi*****

Ta có : 5 = 1 x 5 = (-1) x (-5) = 5 x 1 = (-5) x (-1)

Với : \(\hept{\begin{cases}x-1=1\\y+2=5\end{cases}}\Rightarrow\hept{\begin{cases}x=2\\y=3\end{cases}}\)

\(\hept{\begin{cases}x-1=-1\\y+2=-5\end{cases}}\Rightarrow\hept{\begin{cases}x=0\\y=-7\end{cases}}\)

\(\hept{\begin{cases}x-1=5\\y+2=1\end{cases}}\Rightarrow\hept{\begin{cases}x=6\\y=-1\end{cases}}\)

\(\hept{\begin{cases}x-1=-5\\y+2=-1\end{cases}}\Rightarrow\hept{\begin{cases}x=-4\\y=-3\end{cases}}\)

Vậy x = 2, y = 3 ; x = 0, y = -7; x = 6, y = -1; x = -4, y = -3

=>x^2-6x+9=\(\frac{4\left(4^{16}+16\right)}{4^{16}+16}\)
=>x^2-6x+9=4

=>x^2-6x+5=0

=>(x^2-x)-(5x-5)=0

=>x(x-1)-5(x-1)=0

=>(x-1)(x-5)=0

=>\(\orbr{\begin{cases}x-1=0\\x-5=0\end{cases}}\)

=>\(\orbr{\begin{cases}x=1\\x=5\end{cases}}\)

vậy x=1;x=5

a) \(3,5x-25=60.\frac{3}{4}\Leftrightarrow3,5x-25=45\)

\(\Leftrightarrow3,5x=45+25\Leftrightarrow3,5x=70\Leftrightarrow x=\frac{70}{3,5}=20\)

b) \(-1\frac{1}{2}x+\frac{1}{5}=2\frac{3}{10}\Leftrightarrow\frac{-3}{2}x=\frac{23}{10}\Leftrightarrow x=\frac{23}{10}:\frac{-3}{2}=\frac{-23}{15}\)

a)\(3,5x-25=60:\frac{3}{4}=80\)

\(3,5x=80+25\)

\(3,5x=105\)

\(x=105:3,5\)

\(x=30\)

b) \(\frac{-3}{2}x+\frac{1}{5}=\frac{23}{10}\)

\(\frac{-3}{2}x=\frac{23}{10}-\frac{1}{5}=\frac{21}{10}\)

\(x=\frac{21}{10}:\frac{-3}{2}\)

\(x=\frac{-7}{5}\)

21342+4214= 25556

lâu rồi ko ns chuyện nhỉ linh

\(P=\frac{5}{2.1}+\frac{4}{1.11}+\frac{3}{11.2}+\frac{1}{2.15}+\frac{13}{15.4}+\frac{15}{4.43}+\frac{13}{43.8}\)

\(\Leftrightarrow\)\(\frac{1}{7}P=\frac{1}{7}\left(\frac{5}{2.1}+\frac{4}{1.11}+\frac{3}{11.2}+\frac{1}{2.15}+\frac{13}{15.4}+\frac{15}{4.43}+\frac{13}{43.8}\right)\)

                   \(=\frac{5}{2.7}+\frac{4}{7.11}+\frac{3}{11.14}+\frac{1}{14.15}+\frac{13}{15.28}+\frac{15}{28.43}+\frac{13}{43.56}\)

                   \(=\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+\frac{1}{14}-\frac{1}{15}+\frac{1}{15}-\frac{1}{28}+\frac{1}{28}-\frac{1}{43}+\frac{1}{43}-\frac{1}{56}\)

                    \(=\frac{1}{2}-\frac{1}{56}=\frac{27}{56}\)

\(\Leftrightarrow\)\(P=\frac{27}{56}:\frac{1}{7}=3\frac{3}{8}\)\(>3\)  (ĐPCM)

1/7p= 5/2.7+4/7.11+...+13/43.56

1/7p=1/2-1/7+1/7-1/11+...+1/43-1/56

1/7p=1/2-1/56

1/7p=27/56

suy ra p=27/56.7

p=189/56>3 suy ra đéo phải chứng minh

ai mà tính được ??

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1:19/15-7/2

=19/15-7/2

=67/30

2/5+3/5:{3/5+-2/3}-3/1/2

=2/5+3/5;{9/15+10/15}-3/1/2

=2/5+3/5:19/15-7/2

=2/5+3*15/5*19-7/2

=2/5+9/19-7/2

=38/95+45/95-7/2

=83/95-7/2

=166/190-665/190

=-499/190

5^299=(5^2)^297=25^297

3^501=(3^3)^493=27^493

do 25<27 và 297<493 => 25^297<27^493 => 5^299 < 3^501

bài 3

số học sinh lớp 6a là

120x35%=42(học sinh)

số học sinh lớp 6c là

120x3/10=36(học sinh)

số học sinh lớp 6b là

120-42-36=42(hoc sinh)

vì ko có thời gian nên mình giải đượcbai 3 thoi

nhớ k cho mình nha

hu hu giúp mihf vs