So, since these two fractions do not have like denominators, we need to find one. To do this, you can just multiply the denominators of -1/2 and -3/5 to get a like denominator...like 10.
Now, you need to fix the numerators.
What times 2 makes 10? 5!
So, multiply -1*5=-5.
Now, what times 5 makes 10? 2!
So, multiply -3*2=-6.
Now just solve -5/10-6/10=-11/10 or -1 and 1/10.
Hope this helped!
