Add `4a b ,\ -7a b ,\ -10 a b\ a n d\ 3a bdot`

Add 3a^2b ,\ 2a^2b ,\ 13 a^2b and a^2bdot

In the adjoining figure A B D C\ a n d\ D A is perpendicular to A Bdot Further, D C=7c m ,\ C B=10 c m\ a n d\ A B=13 c mdot Find the area of the quadrilateral A B C Ddot

Find the angle between the pairs of lines with direction ratio proportional to: a ,\ b ,\ c\ a n d\ b-c ,\ c-a ,\ a-bdot

Add : 5a + 3b, a - 2b, 3a + 5b

Add : 6- 3a + b , a - 7-6b and 3b + 2- a.

Find the point of intersection of the following pairs of lines: b x+a y=a b\ a n d\ b x+a y=a bdot

If the origin is the centroid of the triangle with vertices P(2a ,\ 2,6),\ Q(-4,3b ,-10) a n d \ R(8, 14 ,2c) , find the values of a\ a n d\ bdot

If vec c is perpendicular to both vec a\ a n d\ vec b , then prove that it is perpendicular to both vec a+ vec b\ a n d\ vec a- vec bdot

A B C D is a trapezium with parallel sides A B=a\ a n d\ D C=bdot If E\ a n d\ F are mid-points of non-parallel sides A D\ a n d\ B C respectively, then the ratio of areas of quadrilaterals A B F E\ a n d\ E F C D is: a : b (b) (a+3b):(3a+b) (3a+b):(a+3b) (d) (3a+b):(3a+b)

Let A={a , b , c , d},\ B={a , b , c}a n d\ C={b , d} . Find all sets X such that: XsubA\ a n d\ Xsub Bdot