4.2=-5a-1.6

Solution for 4.2=-5a-1.6 equation:

Simplifying
4.2 = -5a + -1.6

Reorder the terms:
4.2 = -1.6 + -5a

Solving
4.2 = -1.6 + -5a

Solving for variable 'a'.

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

Add '5a' to each side of the equation.
4.2 + 5a = -1.6 + -5a + 5a

Combine like terms: -5a + 5a = 0
4.2 + 5a = -1.6 + 0
4.2 + 5a = -1.6

Add '-4.2' to each side of the equation.
4.2 + -4.2 + 5a = -1.6 + -4.2

Combine like terms: 4.2 + -4.2 = 0.0
0.0 + 5a = -1.6 + -4.2
5a = -1.6 + -4.2

Combine like terms: -1.6 + -4.2 = -5.8
5a = -5.8

Divide each side by '5'.
a = -1.16

Simplifying
a = -1.16