Answer:
35 - 5a = - (1 - 4a)
remove bracket, change signs as needed
35 - 5a = -1 + 4a
bring variables to one side
35 - 5a + 5a = -1 + 4a + 5a
simplify if needed
35 = -1 + 9a
bring numerical values to the opposite side
35 + 1 = -1 +1 + 9a
simplify if needed
36 = 9a
divide to isolate variable 'a'
36 = 9a
9 9
4 = a
therefore 'a' equals 4