Question

(x+5)(x2 - 2x + 3)

Answer 1

I assume that x2 means \[x ^{2}\]
right?

Answer 2

yes

Answer 3

if it is, then multiply each term in first parenthesis to each term in second & combine...:
\[x ^{3}-2x ^{2}+3x+5x ^{2}-10x+15=x ^{3}+3x ^{2}-7x+15\]