To solve the equation (-3/7)y = (-6/7)*2.5, we first need to simplify the right side of the equation:

(-6/7)*2.5 = -15/7

Now we can substitute this value back into the original equation:

(-3/7)y = -15/7

To solve for y, we multiply both sides by the reciprocal of (-3/7), which is -7/3:

y = (-15/7) * (-7/3)

y = 35/7

Therefore, the solution to the equation (-3/7)y = (-6/7)*2.5 is y = 5.