-1 14/15
— Turn -1 1/3 into an improper fraction.
1 1/3 = (1x3)+1 = 4/3
3/5 stays the same.
Now change them to have equal denominators.
3x5 = 15 which is a multiple of both. Now multiply 5x4 to replace the numerator for 4/3. Multiply 3x5 for 3/5.
= 20/15 + 9/15 = 29/15 = -1 14/15 simplified.