What’s the answer i don’t understand ?

Factorize: x^2+8x+10 i just solved it but i don't know if the process is correct

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

Tabby sells clothing at a retail store, and she earns a commission of 6.25% on all items she sells. last week she sold a pair of jeans for $32.50, a skirt for $18.95, and 2 blouses for $14.95 each. what was tabby's total commission? a $4.15 b $5.08 c $81.35 d $348.60