Help please help please math

Which triangles area would be calculated using the trigonometric area formula

Use mathematical induction to prove the statement is true for all positive integers n, or show why it is false. 1^2 + 4^2 + 7^2 + + (3n - 2)^2 = [n(6n^2-3n-1)/2]

The image of abc after a reflection across eg is abc