Question

7×7×13+13 is a composite number. Justify

Answer 1

7(1×1×13+13) + 13(7×7×1+1)..
7(13+13) + 13(49+1)..
7(26) + 13(50)...
182 + 650...
832 ...
832 is a composite number that's why 7×7×13+13 is a composite number...