Solve for k -3-0.1k=0.4k

$- 3 - 0.1 k = 0.4 k$

Move all terms containing $k$ to the left side of the equation.

Subtract $0.4 k$ from both sides of the equation.

$- 3 - 0.1 k - 0.4 k = 0$

Subtract $0.4 k$ from $- 0.1 k$ .

$- 3 - 0.5 k = 0$

Add $3$ to both sides of the equation.

$- 0.5 k = 3$

Divide each term in $- 0.5 k = 3$ by $- 0.5$ and simplify.

Divide each term in $- 0.5 k = 3$ by $- 0.5$ .

$\frac{- 0.5 k}{- 0.5} = \frac{3}{- 0.5}$

Simplify the left side.

Cancel the common factor of $- 0.5$ .

Cancel the common factor.

$\frac{- 0.5 k}{- 0.5} = \frac{3}{- 0.5}$

Divide $k$ by $1$ .

$k = \frac{3}{- 0.5}$

Simplify the right side.

Divide $3$ by $- 0.5$ .

$k = - 6$