Find two consecutive whole numbers such that 3/4 of the first number is 5 more than the second number.

translate the words to symbols.

Let the two numbers be a and b
b = a+1
3/4 a = b+5

now substitute a+1 everywhere b shows up
3/4 a = a+1+5 = a+6

clear the fraction by multiplying by 4

3a = 4a + 24
a = -24
b = -23

3/4 of a is -18
-18 = -23 + 5