Answer:
Simplified: 12(x^2)-15x+3----if x = 3: 66
Explanation:
When you simplify expressions, you have to take out the parentheses, so we just multiply 3x by everything inside the parentheses. So 3x(4x-5) we get 12(x^2) - 15x and then we just add the 3 so we get 12(x^2)-15x+3. Now all we have to do is substitute x as 3, we get 66 as your answer. Sorry if I'm wrong, this is what I got.