单选题
If x is positive and y is two greater than the square of x, which of the following expresses x in terms of y?
- A.
- B.
- C.
【正确答案】
B
【答案解析】When x is positive and y is two greater than the square of x, y=x2+2. To find x in terms of y, solve the equation y=x2+2 for x. First, subtract 2 from both sides to get x2=y-2. Then take the square root of both sides such that y-2 is thought of as a single quantity: [*].