Could you please show the question so I can try to answer it
42 can be
1 x 42, or
2 x 21, or
3 x 14, or
6 x 7 .
Solving to y gives you:y=x+3
The given numbers are 13, 27, 81, 21,43, 48,23,39,45.
Square number is that number which is a perfect square means if you multiply a number by itself the number you obtained is a perfect square i.e it's square root is a natural number.
√13=not a natural number
√27=√3×√3×√3=3√3=irrational number
√81=√9×√9=9=a natural number
√21=not a natural number
√43=not a natural number
√48=4√3=not a natural number
√23=not a natural number
√39=not a natural number
√45=3√5=not a natural number
So, out of following numbers 13 27 81 21 43 48 23 39 45→81 is the only square number.
