Solve for a by adding 2 to each side to get 8a = 24. Divide by 8 to find a = 3. Plug a = 3 into the second equation to find 4(3) − 1 = 12 − 1 = 11. Alternatively, you could save yourself some time by noticing that 8a − 2 is 2(4a − 1). If 2(4a −1) = 22, divide by 2 to get 4a − 1 = 11.