Answer: C. (x+3)(x+10)
Explanation:
Note how the 3 and 10 are two values such that
- They add to 13, which is the middle coefficient, and,
- They multiply to 30, which is the last term
We can use the distribution rule like so to help confirm the answer
(x+3)(x+10)
y(x+10) ... replace x+3 with y
xy+10y .... distribute
x( y ) + 10( y )
x( x+3 ) + 10( x+3 ) .... plug in y = x+3
x^2+3x + 10x+30 .... distribute again twice more
x^2 + 13x + 30 ... combine like terms
