(ab+4a-6)-(ab+6)=0

Solution for (ab+4a-6)-(ab+6)=0 equation:

Simplifying
(ab + 4a + -6) + -1(ab + 6) = 0

Reorder the terms:
(-6 + 4a + ab) + -1(ab + 6) = 0

Remove parenthesis around (-6 + 4a + ab)
-6 + 4a + ab + -1(ab + 6) = 0

Reorder the terms:
-6 + 4a + ab + -1(6 + ab) = 0
-6 + 4a + ab + (6 * -1 + ab * -1) = 0
-6 + 4a + ab + (-6 + -1ab) = 0

Reorder the terms:
-6 + -6 + 4a + ab + -1ab = 0

Combine like terms: -6 + -6 = -12
-12 + 4a + ab + -1ab = 0

Combine like terms: ab + -1ab = 0
-12 + 4a + 0 = 0
-12 + 4a = 0

Solving
-12 + 4a = 0

Solving for variable 'a'.

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

Add '12' to each side of the equation.
-12 + 12 + 4a = 0 + 12

Combine like terms: -12 + 12 = 0
0 + 4a = 0 + 12
4a = 0 + 12

Combine like terms: 0 + 12 = 12
4a = 12

Divide each side by '4'.
a = 3

Simplifying
a = 3