Show that lines `x-2y-7=0`and `2x+y+1=0`are perpendicular to each other. Find their point of intersection.

Show that lines x-2y-7=0 and 2x-4y+15=0 are parallel to each other.

If the straight lines 2x+ 3y -3=0 and x+ky +7 =0 are perpendicular, then the value of k is

Show that lines 3x-4y+5=0,7x-8y+5=0 and 4x+5y-45=0 are concurrrent.Find their point of concurrence.

If the lines 2x+3ay-1=0 and 3x+4y+1=0 are matually perpendicular, then the value of a will be

The equation of a line passing through the point of intersection of lines x+2y +3 =0 and 3x+4y +7=0 and perpendicular to the line x-y+9 =0 is

The two lines represented by 3a x^2+5x y+(a^2-2)y^2=0 are perpendicular to each other for

Solve the following:Show that the line 3x-4y+15=0 is a tangent to the circle x^2+y^2=9 ,Find the point of contact.