Its most likely -1 if its not then its 5
An equation derived by the twentieth-century physicist Albert Einstein, in which E represents units of energy, m represents units of mass, and c 2 is the speed of light squared, or multiplied by itself.
-15/-21 -14/x
-15x = -21 * -14
x = -19.6
answer -14c = -19.6 or about -20
answer 3c = .6 or about 1
formula would be
y= 1.2x -3
partial variation means the line doesn't go through (0,0)