3.8=-k(10)

Solution for 3.8=-k(10) equation:

Simplifying
3.8 = -1k(10)

Reorder the terms for easier multiplication:
3.8 = -1 * 10k

Multiply -1 * 10
3.8 = -10k

Solving
3.8 = -10k

Solving for variable 'k'.

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

Add '10k' to each side of the equation.
3.8 + 10k = -10k + 10k

Combine like terms: -10k + 10k = 0
3.8 + 10k = 0

Add '-3.8' to each side of the equation.
3.8 + -3.8 + 10k = 0 + -3.8

Combine like terms: 3.8 + -3.8 = 0.0
0.0 + 10k = 0 + -3.8
10k = 0 + -3.8

Combine like terms: 0 + -3.8 = -3.8
10k = -3.8

Divide each side by '10'.
k = -0.38

Simplifying
k = -0.38