From the first figure pattern, we can observe that
term in east direction i.e. xy
+
term in west direction i.e. x2
=term in south direction i.e. x2+xy
&
term in east direction i.e. xy
×
term in west direction i.e. x2
=term in north direction i.e. x3y
According to the same pattern, we can find a & b values in the second pattern.
7x×a=7x2y⇒a=7x2y7x=⇒a=xy
&
7x+a=b⇒7x+xy=b
b−a=7x+xy−xy=7x
∴ At x=1,
the value of (b−a)=7×1
=7