3 x 10 sama dengan 2 dikurangi X

3 x 10 = 2 – x
30 + x = 2 – x + x
30 – 30 + x = 2 – 30
x = -28

3×10 = 2-x
30 = 2 – x
30-2 = -x
28 = -x          
-28 = x