Find the sum to indicated number of terms in each of the following geometric progressions. `sqrt(7),sqrt(21),3sqrt(7)`,……n terms.

Find the sum to indicated number of terms of the geometric progressions given below:- sqrt7,sqrt21, 3sqrt7 ,.....n terms.

Find the sums of the indicated number of terms of the following geometric progressions : x^2-y^2,x-y, (x-y)/(x+y) , ...., n terms (x+y ne 1) .

Find the sums of the indicated number of terms of the following geometric progressions : 2,-1/2,1/8 , ........., n terms, 12 terms.

Find the sums of the indicated number of terms of the following geometric progressions : 1,1/3,1/9 .........., n terms, 5 terms.

Simplify each of the following expressions : (sqrt13-sqrt7)(sqrt13-sqrt7) .

Simplify each of the following expressions : (7+sqrt3)(4+sqrt5) .

Find the sum of indicated number of terms of the following arithmetic progression : 16, 11, 6,..........., n terms, 23 terms.

Find the sum to indicated number of terms of the geometric progressions given below:- 1,-a, a^2,-a^3 , ... n terms (if a ne -1 ).

Find the number of terms in each of the following APs :- 7, 13, 19,..., 205 .