Answer:
a = -5
Explanation:
Given
-18 + 2a = 2(3a + 1)
Expand the bracket on the right
-18 + 2a = 2 x 3a + 2 x 1
-18 + 2a = 6a + 2
Add 18 to both sides
-18 + 18 + 2a = 6a + 2 + 18
2a = 6a + 20
Subtract 6a from both sides
2a - 6a = 6a - 6a + 20
-4a = 20
Divide both sides by -4
-4a/-4 = 20/-4
a = -5