Question

explain why 7×11×13+13 and 7×6×5×4×3×2×1+5 are composite numbers
please reply fast

Answer 1

hello there!!!
they r composite numbers since 7×11×13+13 can be written as (7×11×1+1)13 and 7×6×5×4×3×2×1+5 can be written as (7×6×1×4×3×2×1+1)5
remember the definition of composite numbers and u will understand :)

Answer 2

yeah i know..............
see
composite numbers are those which contain more than two common factors......
so lets solve these numbers...
.taking first number......
7*11*13+13
13(7*11+1)
13(77+1)
13 * 78
13*13*3*2.........................................(i)

taking second number....
7*6*5*4*3*2*1 +5
5(7*6*4*3*2+1)
5* 984
5*3*164*2....................................(ii)
now see (i) and (ii)
both have 2 and 3 as common
also they have two other factors that are one and itself.....
so in total there are 4 common factors
( see definition of composite numbers above)
so they are composite..........