Which of the points A (2; 8), B (-3; 18), C (-3.9) and D (3.18) lie on the graph of the function y = 2x²?

A point belongs to the graph if its coordinates, when substituted into the graph formula, turn into the correct equality. The point has two coordinates: the first is x, the second is y.

1) A (2; 8), y = 2x ^ 2.

Substitute instead of x = 2, y = 8 in the formula y = 2x ^ 2.

8 = 2 * 2 ^ 2;

8 = 2 * 4;

8 = 8, it is true, point A (2; 8) belongs to the graph y = 2x ^ 2.

2) B (- 3; 18)

18 = 2 * (-3) ^ 2;

18 = 18, point B belongs to;

3) C (- 3; 9)

9 = 2 * (-3) ^ 2;

9 ≠ 18, point C does not belong to the graph y = 2×2;

4) D (3; 18)

18 = 2 * 3 ^ 2;

18 = 18, D belongs to.