How to determine whether a change relation is a function? Is Y & # 178; = 3x a function?

For every value of X, y has only one value corresponding to it, so y is a function of X
let me put it another way:
Let X be a known number and y be an unknown number. If y has more than one solution, then it is not a function of X
y²=3x
Y = √ (3x) or - √ (3x) has two solutions, so it is not a function

RELATED INFORMATIONS

1. Let m and n (m ≠ 0) be constants. If in the positive proportional function y = KX, the independent variable x increases m and the corresponding function y increases n, then the value of K is () A. k＝nmB. k＝mnC. k＝−nmD. k＝−mn
2. It is known that y is a positive proportional function of X. when the independent variable x increases by 5, the value of Y decreases by 7
3. Is y = 1 / x a positive proportional function (x is an independent variable)
4. Given a positive proportional function, when the dependent variable y increases by 3, the independent variable x increases by 9, then the relation of this function is
5. In the following functions, X is an independent variable and Y is a dependent variable. Which are primary functions and which are positive proportional functions? (1) Y = 5 of X (2) y = 5 of X (3) y = - 3x + 1 (4) y = x & sup2; - 1 (5) - 2 of X + 1 Give reasons
6. If the function y = 3x2 - (9 + a) x + 6 + 2A (x is an independent variable and X is an integer) gets the minimum value when x = 6 or x = 7, then the value range of a is______ ．
7. Given the function y = √ - 3x-6-7, when the independent variable x takes what value, the function y has the minimum value? And find the minimum value
8. Draw the image of y = 3x-6 when - 1 ≤ X
9. (6) When the value of independent variable x satisfies what conditions, the value of function y = 3x-5 satisfies the following conditions? (7) using function image to solve X (6) When the value of independent variable x satisfies what conditions, the value of function y = 3x-5 satisfies the following conditions? (1) y =0(2)y =10 (3) y = - 20 (7) use function image to solve x, and check (1) 2x + 3 = 9 (2) 5x-3 = x + 1 (8) the current velocity of an object is 4 m / s, its velocity increases by 3 M / s, in a few seconds, its velocity is 13 m / S? 34 m / S?
10. When the line y = 3x + 2 moves down one unit, a new function image is obtained. When the value of the new function is less than 0, the value range of the independent variable x is A x is less than - 2 / 3 B x is greater than - 1 / 3 C x ＜ - 1 / 3 D x = - 1 / 3
11. What is the solution of the equations 2x + y = 2,2x + y = 5? Then what is the relationship between the images of this function y = 2-2x and y = 5-2x
12. What are the advantages and disadvantages of solving equations, solving inequalities and function images?
13. Solve the equation (4x-1) ^ 2-3 (1-4x) - 4 = 0 (at least in two ways) (4x-1) ^ 2 = - 4x-1 squared
14. How to draw the function image of 4x-4 = 0?
15. The number of zeros of function f (x) = 2x-x & # 178; - 2 / X in (0, + ∞) is?
16. Function f (x) = 2lnx - X & # 178; - KX (K ∈ R), if function f (x) has two zeros m, n (0 ＜ m ＜ n), and 2x0 = m + n. question: can the tangent of function f (x) at the point (x0, f (x0)) be parallel to the X axis? If so, find the tangent equation; if not, explain the reason
17. If f (x) = 2x & # 178; - MX- If the function f (x) = 2x & # 178; - MX-3 is an increasing function when x ∈ [2, positive infinity] and a decreasing function when x belongs to (negative infinity, - 2), then f (1) is equal to? And solved by the most basic method,
18. I'm preview now! Determine whether the following is a function relation. Y = + - x, y = x & #; When x = 1, y has two corresponding values, so y is not a function of X. when x = 1, - 1, y has a definite value of 1, so it is a functional relationship. So I want to ask, this problem does not tell who is a variable and who is a constant. Then I regard y as a variable, and when y = 1, x = + - 1, there are two corresponding values. Is it not a functional relationship? I'm a sophomore in junior high school. I just preview the new content tonight, Weak ask you big brother ~ swelling? Can only see x?
19. It is known that the image of the first-order function y = 3x + 3 intersects with the x-axis at point a and the y-axis intersects with point B, and the image of the second-order function y = - x ^ 2 + BX + C passes through two points a and B 1) There is a point m on the parabola, so that the area of △ mAb is equal to the area of △ OAB, and the coordinates of point m are obtained 2) On the line AB, there is a point P passing through P, making a parabola at the intersection of L / / X axis and C D (C is on the left side of D). If PC + PD = 6, find the coordinates of point P
20. The function y = 1-x & # 179; if the image is translated according to the vector a = (0,1), the function expression corresponding to the translated image is