28a+-21a-6=-10.2

Solution for 28a+-21a-6=-10.2 equation:

Simplifying
28a + -21a + -6 = -10.2

Reorder the terms:
-6 + 28a + -21a = -10.2

Combine like terms: 28a + -21a = 7a
-6 + 7a = -10.2

Solving
-6 + 7a = -10.2

Solving for variable 'a'.

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

Add '6' to each side of the equation.
-6 + 6 + 7a = -10.2 + 6

Combine like terms: -6 + 6 = 0
0 + 7a = -10.2 + 6
7a = -10.2 + 6

Combine like terms: -10.2 + 6 = -4.2
7a = -4.2

Divide each side by '7'.
a = -0.6

Simplifying
a = -0.6