[tex]\displaystyle{ x = a^{2} + a }[/tex]
[tex]\displaystyle{ y = a - 1 }[/tex]
[tex]\displaystyle{ z = a^{2} - 1 }[/tex]
[tex]\displaystyle{ \frac{x\cdot y}{z} = \frac{(a^{2}+a) \cdot (a - 1)}{a^{2}-1} }[/tex]
[tex]\displaystyle{ \frac{x \cdot y }{z} = \frac{(a^{2} + a) \cdot (a - 1)}{(a-1) \cdot (a+1)} }[/tex]
[tex]\displaystyle{ \frac{x \cdot y}{z} = \frac{a^{2}+a}{a+1} = \frac{a \cdot (a + 1)}{a+1} }[/tex]
[tex]\displaystyle{ \frac{x \cdot y}{z} = a }[/tex]
Răspuns:
Explicație pas cu pas:
x=a²+a=a(a+1)
y=a-1
z=a²-1=(a-1)(a+1)
xy/z=a(a+1)(a-1)/(a+1)(a-1)=a
