Precalculus, Chapter 6, 6.3, Section 6.3, Problem 36

You need to evaluate the sum of two vectors,u+v , hence you need to perform the addition of the same versors, such that:
u = -2i + j
v = 0i + 3j
u + v = (-2+0)i + (1+3)j
u + v = -2i+4j
Hence, evaluating the sum u + v yields u + v = -2i+4j.
You need to evaluate the difference of two vectors,u-v , hence you need to perform the subtraction of the same versors, such that:
u = -2i + j
v = 0i + 3j
u - v = (-2-0)i + (1-3)j
u - v = -2i-2j
Hence, evaluating the difference u - v yields u - v = -2i-2j.
You need to evaluate the difference of the vectors,2u-3v , hence you need to perform first the multiplication of each vector with the indicated scalar and then you need to perform the subtraction of the same versors, such that:
u = -2i + j=> 2u = -4i + 2j
v = 0i + 3j => 3v = 0i + 9j
2u - 3v = -4i + 2j - 0i - 9j => 2u - 3v = -4i - 7j
Hence, evaluating the difference 2u - 3v yields 2u - 3v = -4i - 7j.