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
