What is the equation of the straight line parallel to 2x + 3y + 1 = 0 and passes through the point ($$-$$1, 2) ?

What is the acute angle between the pair of straight lines $$\sqrt 2 x + \sqrt 3 y = 1$$ and $$\sqrt 3 x + \sqrt 2 y = 2$$ ?

If the centroid of a triangle formed by (7, x), (y, $$-$$6) and (9, 10) is (6, 3), then the values of x and y are respectively

The angle between the two lines $$lx + my + n = 0$$ and $$l'x + m'y + n' = 0$$ is given by $${\tan ^{ - 1}}\theta $$. What is $$\theta$$ equal to?