Please, I need help with this

14 + 3a = 3 - 4(5a + 3)

Simplify

14 + 3a = 3 - 20a - 12

Subtract 3a from both sides

14 = 3 - 23a - 12

Simplify

14 = -9 - 23a

Add 9 on both sides

23 = -23a

Subtract -23 on both sides

-1 = a

And there you go :)