The information given places no restriction at all on the value that x can have. It can be any number - integer, rational, irrational or complex - of any magnitude.
negative 15
2x3 + x2 + 15 This is a 3rd order polynomial in 'x'. It's numerical value kinda depends on the value of 'x'.
That depends entirely on the value of x.
That heavily depends on the value of 'x'.
30 + 5x = 15 + 10x 30 = 15 + 5x 15 = 5x x = 3
There is not enough information to solve for x. x+5x+15 must equal something (is it 0?) in order to solve for x.
what the solution to this equation x+15=28 If you mean: x+15 = 28 then the value of x works out as 13
-15
3(2)-9=15 x=2
find x+x+x when x=15 15+15+15=45
15 (x = 135)
That depends on what the value of x is.