Find 8 values of c that make the following expression factorable. x^2+3x+c. How did you know?

Answer 1

You need 2 numbers which have a sum or difference of 3, c will be their product
e.g.
1,2 , product = 2 , c = 2 ----- (x+1)(x+2) = x^2 + 3x + 2
5, -2, product = -10 , c = -10 ----- (x+5)(x-2) = x^2 + 3x - 10
7, -4 , product = -28 , c = -28 ----- (x+7)(x-4) = x^2 + 3x - 28
-1, 4 , ................ x^2 + 3x - 4
sofar I have
c = 2, -10, -28, -4, ....

continue