Question

Factors of y2+ 10y+21 are……


1. (y+3) and (y-7)
2. (y-3) and (y+7)
3. (y-3) and (y-7)
4. (y+3) and (y+7)

Answer 1

Answer:

Answer is 4.

Step-by-step explanation:

y2+10y+21=0

or, y2+ 7y+3y+(7x3)=0

or, y(y+7)+3(y+7)=0

or, (y+7)(y+3)=0

either, (y+7)=0 or, (y+3)=0

Answer 2

Answer:

y2+10y+21= (y2+3y)+(7y+21)

= y(y+3)+7(y+3)

=(y+3)(y+7)