D, because you can only buy a drum set if you save your allowance and you cannot buy a drum set if you don't save your allowance
For a survey like this, you want to take a random sample. It would be a good idea to use an alphabetical list of the students. Then, you could randomly select students from the list.
The principal would want to avoid surveying all the same type of students. For example, don't just ask the athletes.
The solution for this question is simple. First we need to divide both numbers by 2 which will give us 10 and 7. This is the equation x^2/10^2 + y^2/7^2 = 1sqrt(100-49) = 7.14 (the answer do not have a perfect square root)
Foci are 14.28 units apart
I'm assuming that you meant:
y = 7x² + 3
Remember! Inputs are always x values (unless stated otherwise). Meaning the problem says:
x = 4
y = 7(4)² + 3
The square only applies to the 4. The 7 is not going to be squared! (To be exact it only applies to whatever the value of x is.
4² = 4·4 = 16
Remember:
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction
Follow PEMDAS from left to right (or in the case above from top to bottom).
7·16 + 3 = ?
16·7 = 10·7 + 6·7 = 70 + 42 = 112
(All I did to multiply was break it up into parts. If it confuses you don't worry about it, and just multiply it out like normal or use a calculator if you are allowed to)
112 + 3 = ?
Our output is:
115!