Dopolni naslednje račune.
(a+2)·(b+3)=ab+3a+2b+
(x+1)·(x+3)=x2+
+x+3=x2+
+3
(x+y)·(x+3)=x2+
+ yx+3y
(a+2)·(b+3)=ab+3a+2b+
(x+1)·(x+3)=x2+
+x+3=x2+
+3
(x+y)·(x+3)=x2+
+ yx+3y