Direction cosines of negative z axis

in figure <pqr=<prq,provethat<pqs=<prt

find the value of p(-2/3)forp(y)=2y3-y2-13y-6

It isgiven that 3a+ 2b=5c, then find the value of 27a^3+8b^3-125c^3if abc=0

Prove that each pair of opposite side of quadrilateral is equal then it is a parallelogram 

The locus of the point of intersection of perpendicular tangets to the hyperbola X2/16 -x2/9=1 is

Sir plzz give me important theorem of chapter 19

Sir plzz give me important theorem of chapter 19

Find the mean of the following data: Class Interval 10 – 25 25 – 40 40 – 55 55 – 70 70 – 85 85 – 100 Frequency 2 3 7 6 6 6

there is a mistake in solution.

plz check

Important questions for annual exams of class 11 science 2017-18