0.7a-0.9y-0.8a=

Solution for 0.7a-0.9y-0.8a= equation:

Simplifying
0.7a + -0.9y + -0.8a = 0

Reorder the terms:
0.7a + -0.8a + -0.9y = 0

Combine like terms: 0.7a + -0.8a = -0.1a
-0.1a + -0.9y = 0

Solving
-0.1a + -0.9y = 0

Solving for variable 'a'.

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

Add '0.9y' to each side of the equation.
-0.1a + -0.9y + 0.9y = 0 + 0.9y

Combine like terms: -0.9y + 0.9y = 0.0
-0.1a + 0.0 = 0 + 0.9y
-0.1a = 0 + 0.9y
Remove the zero:
-0.1a = 0.9y

Divide each side by '-0.1'.
a = -9y

Simplifying
a = -9y