m is a whole number less than 5 Whole numbers less than 5 are 0, 1, 2, 3 and 4 hence m can take values 0, 1, 2, 3 and 4

When m = 0:

2m – 5 = 2 × 0 – 5 = -5

When m = 1:

2m – 5 = 2 × 1 – 5 = 2 – 5 = -3

When m = 2:

2m – 5 = 2 × 2 – 5 = 4 – 5 = -1

When m = 3:

2m – 5 = 2 × 3 – 5 = 6 – 5 = 1

When m = 4:

2m – 5 = 2 × 4 – 5 = 8 – 5 = 3

The table becomes

By looking at table the equation 2m – 5 = – 1 holds true when m = 2 hence solution of equation 2m – 5 = – 1 is m = 2