please friends help me outwith these sums

1)If the sum of first n terms of two arithmetic progression are in the ratio

(7n + 1) 4n + 27), find the ratio of their 11th terms.

2)Find the sum of first n terms of the series

3 × 8 + 6 ×11 + 9 × 14 + ....

3)Let f(x) = x2 + 3, g(x) = x – 2, then find fog and gof. Also, show that (fog) (3/2) =(gof) (3/2).

4)Solve the equation:

Sin x + Sin 2x + Sin 3x + Sin 4x = 0