factor by grouping: y squared - 9y + 7y - 63

Question

It's factoring of grouping which I tired doing. I don't any of the first steps and what to do.

Answer 1

(y²-9y)+(7y-63)

y(y-9)+7(y-9)

(y-9)(y+7)

Answer 2

-9y+7y can be added to give -2y

 

y^2-2y-63

 

63 factors are 9 and 7 since -2y is a negative the bigger number in between these two numbers will carry the negative sign which is the 9 when factoring.

 

(y-9)(y+7)

 

now y=+9

       y=-7

 

note the change in signs for y from factored form.