30dē + 34d + 8 = 0
Divide every term by 2:
15dē + 17d + 4 = 0
Factor the left side
(5d + 4)(3d + 1) = 0
Now the principle of zero product explained:
This says (5d + 4) multiplied by (3d + 1) equals zero.
The only way that can possibly happen is for one of
them to equal zero.
So either 5d + 4 equals zero or 3d + 1 equals 0.
So we write and solve the two equations:
5d + 4 = 0 3d + 1 = 0
5d = -4 3d = -1
d = d =
There are two solutions, one for each of those two