Answer:-7
Step-by-step explanation: -343 is your total so first off you need to try and isolate T. The way I done it was -343 was my total and I started with 5x5x5 which is 125 so I moved up to 6x6x6 which is 216 so I went up to 7x7x7 which is 343 and our total is negative so its -7