Question

am nevoie de ajutor va rog
peste 4 zile dau test din asta ​

Answer 1

Răspuns:

Explicație pas cu pas:

fie x numar par x=2k

x²-x=(2k)²-2k=4k²-2k=

2(2k²-2)=numar par

fie x numar impar   x=2k+1

(x²)-x=(2k+1)²+1=4k²+4k+1+1=

4k²+4k+2=2(2k²+2k+1)= numar par

Deci x²-x= numar par pt orice  x

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[(x+1)/x+(2x+2)/(x²-x)]:(2x+2)/(x²-x)=

[(x+1)/x+(2x+2)/(x²-x)]*(x²-x)/(2x+2)=

(x+1)/x*(x²-x)/(2x+2)+(2x+2)/(x²-x)*(x²-x)/(2x+2)=

(x+1)/x*X(x-1)/2(x+1)+1=

(x-1)/2+1=x/2-1/2+1=

x/2+1/2=

(x+1)/2