-.4(n+3)=10

Solution for -.4(n+3)=10 equation:

Simplifying
-0.4(n + 3) = 10

Reorder the terms:
-0.4(3 + n) = 10
(3 * -0.4 + n * -0.4) = 10
(-1.2 + -0.4n) = 10

Solving
-1.2 + -0.4n = 10

Solving for variable 'n'.

Move all terms containing n to the left, all other terms to the right.

Add '1.2' to each side of the equation.
-1.2 + 1.2 + -0.4n = 10 + 1.2

Combine like terms: -1.2 + 1.2 = 0.0
0.0 + -0.4n = 10 + 1.2
-0.4n = 10 + 1.2

Combine like terms: 10 + 1.2 = 11.2
-0.4n = 11.2

Divide each side by '-0.4'.
n = -28

Simplifying
n = -28