(3.4a-1.7b)+(2.5a-3.9b)=

Solution for (3.4a-1.7b)+(2.5a-3.9b)= equation:

Simplifying
(3.4a + -1.7b) + (2.5a + -3.9b) = 0

Remove parenthesis around (3.4a + -1.7b)
3.4a + -1.7b + (2.5a + -3.9b) = 0

Remove parenthesis around (2.5a + -3.9b)
3.4a + -1.7b + 2.5a + -3.9b = 0

Reorder the terms:
3.4a + 2.5a + -1.7b + -3.9b = 0

Combine like terms: 3.4a + 2.5a = 5.9a
5.9a + -1.7b + -3.9b = 0

Combine like terms: -1.7b + -3.9b = -5.6b
5.9a + -5.6b = 0

Solving
5.9a + -5.6b = 0

Solving for variable 'a'.

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

Add '5.6b' to each side of the equation.
5.9a + -5.6b + 5.6b = 0 + 5.6b

Combine like terms: -5.6b + 5.6b = 0.0
5.9a + 0.0 = 0 + 5.6b
5.9a = 0 + 5.6b
Remove the zero:
5.9a = 5.6b

Divide each side by '5.9'.
a = 0.9491525424b

Simplifying
a = 0.9491525424b