Find three consecutive multiples of 4 so that the product of the first and second number is 16 more than 5 times the third number

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