-3x+ 4=1 and -12x -27=324
646/3=x
To check it: x*3 should =646
N-3, n-2, n-1, n and the sum is
4n-6=198 add 6 to both sides
4n=204 divide both sides by 4
n=51
So the fourth number is 51.
The number 0 is basically nothing, so 7 divided by nothing is not defined. That's why calculators or even the most powerful computer can't divide anything by 0