f(x) means the function of x
so the function is the input is x and the output is f(x), read "f of x". The output f(x) is sometimes given an additional name y by y = f(x). The example that comes to mind is the square root function on your calculator.
Answer:
If angle a and b are complementary angles, and angle a is 64, complementary equals 90, so 90-64= 26 degrees for angle b.
First we need to know how much each pen costs. So we take 11.77 and divide it by 11. That gives us 1.07 per pen. So answer choice A has 4 pens for 4.44, so we need to multiply 1.07 x 4. That gives you 4.28, so we know that isn't the correct answer. For option B, we need to multiply 1.07 x 5. That is 5.35, so that also can't be the answer. For C, we need to do 1.07 x 6, and that gives us 6.42. So we know the correct answer is option C.
At the end of the 6 months the balance would be 360.54
I think the answer is 90 degrees