Question

solve the question of math

Answer 1

$a4 = 0 \\ a + 3d = 0 \\ a = - 3d \\ a25 = a + 24d = - 3d + 24d = 21d \\ a11 = a + 10d = - 3d + 10d = 7d \\ a25 = 3 \times 7d \\ a25= 3 \times a11$

Answer 2

l am weak in mathematics.. sorry