0.6-1.6(x-4) = 3(7-0.4x)

0.6-1.6x + 6.4 = 21 - 1.2x

Combine like terms:

6.4 - 1.6x = 21 - 1.2x

Add 1.2x to both sides:

6.4 = 21 - 0.4x

Subtract 21 from both sides:

-14.6 = -0.4x

Divide by -0.4:

x = 36.5

Therefore, the solution to the equation is x = 36.5.