If you multiply an unknown number by 6 and then add 5 , the result is 7 less than the unknown number plus 1 , multiplied by 3. Evaluate the unknown number.

Step 1 ：\(6x + 5 = 3(x + 1) - 7\)

Step 2 ：\(6x + 5 = 3x + 3 - 7\)

Step 3 ：\(6x + 5 = 3x - 4\)

Step 4 ：\(3x = -9\)

Step 5 ：\(x = -3\)

Step 6 ：\(\boxed{-3}\)