i need help with my homework

Question

h(n)= -2n^2 + 4 find h(4)

Answer 1

Given:  h(n) = -2n² + 4
Find:    h(4)

Solution:  Substituting 4 for n we get -2(4²) + 4, which simplifies to -2(16) + 4 and gives us -32 + 4 and our final answer of -28.

Answer 2

Any time you see this function notation, you need to plug in the number in the parantheses everywhere you see the variable.

For example, if you have f(x)=6x-7/x+5x^2 and we need to find f(-1), then we need to plug in "-1" everywhere we see an "x". So we get f(-1) = 6(-1)-7/(-1)+5(-1)^2

Then, as Sirid said, you must follow order of operations.

Answer 3

Remember the rule of PEMDAS when deciding what order to do your calculations - 

1. paretheses
2. exponents
3. multiplication
4. division
5. addition
6. subtraction.

 

In this case it means you'll first solve the exponent n^2 (or 4^2), THEN multiply by -2, THEN add 4.