(2.3y-4.2)+(-3.9y-7.4)=

Solution for (2.3y-4.2)+(-3.9y-7.4)= equation:

Simplifying
(2.3y + -4.2) + (-3.9y + -7.4) = 0

Reorder the terms:
(-4.2 + 2.3y) + (-3.9y + -7.4) = 0

Remove parenthesis around (-4.2 + 2.3y)
-4.2 + 2.3y + (-3.9y + -7.4) = 0

Reorder the terms:
-4.2 + 2.3y + (-7.4 + -3.9y) = 0

Remove parenthesis around (-7.4 + -3.9y)
-4.2 + 2.3y + -7.4 + -3.9y = 0

Reorder the terms:
-4.2 + -7.4 + 2.3y + -3.9y = 0

Combine like terms: -4.2 + -7.4 = -11.6
-11.6 + 2.3y + -3.9y = 0

Combine like terms: 2.3y + -3.9y = -1.6y
-11.6 + -1.6y = 0

Solving
-11.6 + -1.6y = 0

Solving for variable 'y'.

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

Add '11.6' to each side of the equation.
-11.6 + 11.6 + -1.6y = 0 + 11.6

Combine like terms: -11.6 + 11.6 = 0.0
0.0 + -1.6y = 0 + 11.6
-1.6y = 0 + 11.6

Combine like terms: 0 + 11.6 = 11.6
-1.6y = 11.6

Divide each side by '-1.6'.
y = -7.25

Simplifying
y = -7.25