You would distribute (multiply) the 5 to the 2x which would then make it 10x and you would distribute (multiply) the 5 to the 3 which would then make it 15. Because the 5 is a positive number the sign stays the same.
Assuming you know how to simplify this, I will not show the steps but can add them later on upon request
Lets use the quadratic formula now
Multiply the numbers 2 * 1 = 2
Moving on, I will do the second part excluding the extra details that I had shown previously as from the first portion of the quadratic you can easily see what to do for the second part.