-3x + 9 - 4 = x + 3 + 2x
-3x + 9 - 4 = 3x + 3
9 - 4 = 6x + 3
5 = 6x + 3
2 = 6x
1/3 = x
I think it’s 72/5 there’s the proof I hope im was helpful
3x-4 is the answer, you have to see that if its 3 times her nieces age it would be 3x and if its four less than that it is 3x-4