1.

-2...4/5....

*Khi x<-2

4-5x=-x-2=> x=6/4=3/2 loại

*khi -2<=x<4/5

4-5x=x+2=> x=2/6=1/3<4/5 nhân

*kho x>=4/5

5x-4=x+2=> x=6/4=3/2 nhận

2.

x(1+y)+y+1=10

(x+1)(y+1)=10

x+1={-10,-5,-2,-1,1,2,5,10}=> x={-11,-6,-3,-2,0,1,4,9}

y+1={-1,-2,-5,-10,10,5,2,1)=> y={-2,-3,-6,-11,9,4,1,0}

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1

x=3/2

\(\frac{1}{x}+\frac{1}{y}=\frac{1}{2}\)

\(\Rightarrow\frac{1}{x}< \frac{1}{2}\)

\(\Rightarrow x>2\left(1\right)\) 

Giả sử x < y \(\Rightarrow\frac{1}{x}>\frac{1}{y}\)

\(\Rightarrow\frac{1}{x}+\frac{1}{x}>\frac{1}{x}+\frac{1}{y}\)

\(\Rightarrow\frac{2}{x}>\frac{1}{2}=\frac{2}{4}\)

\(\Rightarrow x< 4\left(2\right)\)

Từ (1) và (2) => 2 < x < 4

Mà \(x\in Z\Rightarrow x=3\)

\(\Rightarrow\frac{1}{y}=\frac{1}{2}-\frac{1}{3}=\frac{1}{6}\Rightarrow y=6\)

Vậy \(\left[\begin{array}{nghiempt}x=3\\y=6\end{array}\right.\) hoặc \(\left[\begin{array}{nghiempt}x=6\\y=3\end{array}\right.\)

Em chỉ mới lớp 7 thôi

em moi lop 5 thui,check nha anh

em chỉ mới học lớp 5 thôi bài này quá sức rồi!