Răspuns :
[tex]\displaystyle a^2-b^2=18 \\ \\ a-b=9 \\ \\ (a+b)(a-b)=18 \\ \\ 9(a+b)=18 \\ \\ a+b=2[/tex]
a^2-b^2=18
a-b=9
a^2 - b^2 = (a -b) ( a +b)
9 ( a +b ) = 18
a + b = 18 : 9
a + b = 2
a-b=9
a^2 - b^2 = (a -b) ( a +b)
9 ( a +b ) = 18
a + b = 18 : 9
a + b = 2