Answer: (5x + 3)(x + 5)
Use Foil (first, outer, inner, last)
First is 5x multiplied by x which is 5x^2
Outer is 5x multiplied by 5 which is 25x
Inner is 3 multiplied by x which is 3x
Last is 3 multiplied by 5 which is 15
Now we have 5x^2 + 25x + 3x + 15, combine like terms and you get:
5x^2 + 28x + 15