Answer:
4x-9=99
1. Move -9 to the side with 99 and change the sign
4x=99+9
2. Sum
4x=108
3. Divide 4x by 4 to leave the X alone. Do the same on the other side.
4x/4=108/4
4. Complete the division
x=27
Verification:
4(27)-9=99
108-9=99
99=99 (TRUE)
