Given,

y² + 10y + 24

Now first find the numbers whose-

Sum = 10 and

Product = 24

Required numbers are 6 and 4,

So we get;

y² + 10y + 24 = y² + 6y + 4y + 24

= y(y + 6) + 4(y + 6)

= (y + 6)(y + 4)