4.2 is a pure real (rational) number. It has no specific X value.
42
6
It is a quadratic equation and the value of x is -7 or 6 x2 - 42 = (-x) x2 + x - 42 = 0 (x + 7) (x - 6) = 0
If you mean: 3(2+4x) = 42 then the value of x works out as 3
Without an equality sign the expession given is not an equation. But if you mean 8 = 42x then the value od x is 8/42
The answer will depend on the value of x. If x is a square number, then the answer is 42,If x is a factor of 42 then it is 42/x,Otherwise it is 42*x.
42
6
It is a quadratic equation and the value of x is -7 or 6 x2 - 42 = (-x) x2 + x - 42 = 0 (x + 7) (x - 6) = 0
If that's supposed to be a multiplication, the "x" doesn't have a value - it's an operator. The whole expression, on the other hand, does have a value (just do the multiplication).If the "x" is supposed to be an exponent, then it doesn't have a specific value; that is, it may have any value.
48
If you mean: 3(2+4x) = 42 then the value of x works out as 3
-42
This can be written as 16 + x = 42. We know that x, or your "something" is exactly 16 less than 42. All you would have to do to solve it would be to subtract 16 from 42. 42-16=26 so your x value is 26.
-3
100 USD
It starts: 1 x 42 = 42 2 x 42 = 84 3 x 42 = 126 4 x 42 = 168 5 x 42 = 210 6 x 42 = 252 7 x 42 = 294 8 x 42 = 336 9 x 42 = 378 10 x 42 = 420 11 x 42 = 462 12 x 42 = 504 ...