Answer:
a = - 7
Explanation:
given
4a - (6 - 5a) + 12 = 3a + 2(2a - 4) ← distribute parenthesis on both sides
4a - 6 + 5a + 12 = 3a + 4a - 8 ( simplify both sides )
9a + 6 = 7a - 8 ( subtract 7a from both sides )
9a - 7a + 6 = 7a - 7a - 8 ( simplify both sides )
2a + 6 = - 8 ( subtract 6 from both sides )
2a + 6 - 6 = - 8 - 6 ( simplify both sides )
2a = - 14 ( divide both sides by 2 )
a = - 7