Okay. For these types of problems, you must do order of operations (PEMDAS). Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction. Mind you that you do these steps from left to right, and multiplication and division is done from left to right. Same thing with addition and subtraction. With that being said, here are your answers if you do the expressions correctly.
1. 12
2. 106
3. 42
Answer:
4000 
Step-by-step explanation:
V = 1/3(Bh) where B is the area of the base and h is the height of the pyramid
B = 20(20) = 400 h = 30
V = 1/3(400)(30) = 4000 
Tan(theta)= pi
Now, in order for you to find the angle (theta), you would inverse tan both the left and the right to find the value. The inverse of tan is tan^-1.
tan(theta)=pi ---> theta = tan^-1(pi)
Then, you would plug tan^-1(pi) into a calculator, giving you the value
1.26
9514 1404 393
Answer:
n = 6
Step-by-step explanation:
Add 2 and collect terms
3n = 18
Divide by 3
n = 6
Every single one of those polynomials factors. When factored, your expression looks like this:

. When you cancel the like factors out, what you're left with is this:

. That means that b = 9, c = 1, and d = -2