Answer:
1. a=1 b=9 c=20
(x+5) (x+20)
2. a=1 b=2 c=-8
(x-2)(x+4)
Explanation:
When you use the box method, follow these steps (only usable when a=1)
(i'll be using x^2+9x+20 as an example)
be sure to understand that the formula is ax^2+bx+c
1. the top left corner is a, so put x^2
2. the bottom right is the c, or the y intercept. that would be 20 when using x^2+9x+20
3. find 2 numbers that when multiplied equal c and when added equal b. in this problem, 4(5)=20 and 4+5=9, so 4 and 5 belong in the remaining 2 boxes. make sure to add the x after each term, since these terms are b.
4. find to common term in each row of the box (x^2 and 4x share x, and 5 and 20 share 5) and then the common terms in the columns (x^2 and 5x share x and 4 and 20 share 4)
this should give you (x+4)(x+5)
hope this helps!