Can anyone who understands this well take a minute and check my work and see if I did this right?

The book says:

Use the form x^2 - (r1 + r2)x + (r1 * r2)=0

Write a quadratic equation having the given roots.

Problem #1

5,-3

My Work:

Sum of roots: 5+(-3)= 2

Product of roots: 5*-3= -15

so...

answer:

x^2 - 2x - 15=0

Problem #2

6, -1/2

My Work:

Sum of roots: 6+(-1/2)= 5 1/2

Product of roots: 6*-1/2 = -3

Answer:

x^2 - 5 1/2x - 3=0

Is this correct? Thanks in advance.