Answer: x ^ 2 + 8x + 15
Step-by-step explanation: You can use the FOIL method to multiply. F - first two variables, so the two x.
x • x = x^2
O - outside, the outermost variables in the parenthesis, which would be x and 5.
x • 5 = 5x
I - inside, the innermost variables in the parenthesis, which would be x and 3.
x • 3 = 3x
L - last two variables, so 3 and 5.
3 • 5 = 15
Altogether:
x^2 + 5x + 3x + 15, which simplifies to x^2 + 8x + 15.
Image & example for clarity! Hope this helped!