`3sqrt(42875)-?=21`

Factorise : 6sqrt(3)a^(2)-21a+5sqrt(3)

The foci of the hyperbola 3(y-1)^2-4(x-2)^2=12 are (0,sqrt(7)) b. (-2,1-sqrt(7)) c. 2,1-sqrt(7) d. (0)-sqrt(7)

The approximate value of (3sqrt(12))/(2sqrt(28))-:(2sqrt(21))/(sqrt(98)) is (a) 1.0605 (b) 1.0727 (c) 1.6007 (d) 1.6026

A=(1,3,-2) is a vertex of triangle ABC whose centroid is G=(-1,4,2) then length of median through A is sqrt(21) 3sqrt(21) sqrt(21)/2 (3sqrt(21))/(2)

If the angle betweenthe lines whose direction cosines are (-(2)/(sqrt(21)), (C )/(sqrt(21)), (1)/(sqrt(21))) and ((3)/(sqrt(54)), (3)/(sqrt(54)), -(6)/(sqrt(54))) is (pi)/(2) , then the value of C is

If the angle between the lines whose direcrtion cosines are (-(2)/(sqrt(21)),(C)/(sqrt(21)),(1)/(sqrt(21)))and((3)/(sqrt(54)),(3)/(sqrt(54)),(-6)/(sqrt(54))) is (pi)/(2) , then the value of C is