There are n+r points on a plane out of which n points lie on a straight line L and out of the remaining r points that lie outside L, no three points are collinear. What is the number of straight lines that can be formed by joining pairs of there points ?

Sixty points lie on a plane, out of which no three points are collinear. How many straight lines can be formed by joining pairs of points ?

Show that the points (a+5,a-4),(a-2,a+3) and (a,a) do not lie on a straight line for any value of a .

Obtain the equation of straight lines : Passing through the points (2,3) and (-4,1) .

Obtain the equation of straight lines : Passing through the point (a cos^3theta , a sin^3theta) and perpendicular to the straight line x sec theta + y cosec theta = alpha .

A point moves in a straight line so that its displacement x m at time t sec is given by x^2=1+t^2 what is the acceleration in m//sec^2 in time t.

Find the direction in which a straight line must be drawn through the point (1,2) such that its point of intersection with the line x + y -4 = 0 is at a distant 1/3sqrt6 from this point.

A charge - is to be placed at either point A or point B in the figure. Consider points A and B lie on a line that is midway between the to positive charges. Is'the net force experienced at point A (i) greater than, (ii) equal to or (iii) less than the net force experienced at point B? Explain.

The tangent to the curve y = 2x^(2) - 7x + 3 at certain point is parallel to the straight line y = x + 2. Find the equation of this tangent and the point, where it cuts Y-axis.