What is the product of (-a + 3)(a + 4)?

Step-by-step explanation:

multiply the first bracket with the second

and get -a squared -4a+3a+12

then we group like and unlike terms

so -4a+3a = -a

our new equation will be -a (squared)-a+12=0

we equals to zero to remove negative signs and it will be

a squared +a-12

then we find the factors.

And our factors are 3a-4a

=a squared +3a-4a-12=0

We factorise and answer will be

(a+3) (a-4)=0

so a = -3 or 4