+2353 Hi there!
I'm not sure where you're having trouble finding the answer to this question so let me help you.
f(8) means you have a function f(x) where you want to enter x = 8.
In this case your function is $$f(x) = \frac{1}{4}x^4+9x^2-3$$
So if we enter x = 8 into this function we have
$$f(8) = \frac{1}{4} \times 8^4+9 \times 8^2-3$$
Now you probably know the rules of operations in math, so first you would need to calculate
$$8^4 = 4096$$ and $$8^2 = 64$$
This would give us
$$f(8) = \frac{1}{4} \times 4096 + 9 \times 64 - 3$$
second we would need to do the multiplications so
$$\frac{1}{4} \times 4096 = \frac{4096}{4} = 1024$$ and $$9 \times 64 = 576$$
Now we have
$$f(8) = 1024 + 576 - 3$$
This gives
$$f(8) = 1597$$
Reinout-g 
+2353 Hi there!
I'm not sure where you're having trouble finding the answer to this question so let me help you.
f(8) means you have a function f(x) where you want to enter x = 8.
In this case your function is $$f(x) = \frac{1}{4}x^4+9x^2-3$$
So if we enter x = 8 into this function we have
$$f(8) = \frac{1}{4} \times 8^4+9 \times 8^2-3$$
Now you probably know the rules of operations in math, so first you would need to calculate
$$8^4 = 4096$$ and $$8^2 = 64$$
This would give us
$$f(8) = \frac{1}{4} \times 4096 + 9 \times 64 - 3$$
second we would need to do the multiplications so
$$\frac{1}{4} \times 4096 = \frac{4096}{4} = 1024$$ and $$9 \times 64 = 576$$
Now we have
$$f(8) = 1024 + 576 - 3$$
This gives
$$f(8) = 1597$$
Reinout-g
