Okay Element 99 I have been watching relativity and quantum stuff on YouTube, so if you are going all relative on us then you are sending us through Kelvin, which starts at absolute zero, no heat because all motion has stopped.
So: 20*C = 293.15*K 293.15*K x 2 = 586.3*K 586.3*K = 313.15*C
But common sense will show that it can't be the right answer ... 20c is room temperature, 313c is three times higher than boiling water so it can't be right