multiplues of 4 are 4n where n is a natural number
they numbers are 4n,4(n+1), 4(n+2)
(4n)(4(n+1))=16+5(4(n+2))
expand
16n²+16n=16+20n+40
16n²+16n=56+20n
divide both sides by 4
4n²+4n=14+5n
minus 14+5n both sides
4n²-n-14=0
factor
(n-2)(4n+7)=0
set to zero
n-2=0
n=2
4n+7=0
4n=-7
n=-7/4, false, n has to be a natural number
n=2
so
4n=8
4(n+1)=12
4(n+2)=16
the numbers are 8,12,16
