ABC triangle AD and BK bisectors meet at point O. AB = 5, BC = 3, AC = 7 then OK ÷ OB what is -?

Given:
triangle ABC triangle;
AD and BK – bisectors;
point O – the point of intersection of the bisectors;
AB = 5;
BC = 3;
AC = 7;
Find OK ÷ OB;
Decision:
Since the bisector divides the sides into segments in proportion to the adjacent sides, then:
OK / OB = AK / AB = AK / 5 = 7/8;
CK / CB = AK / AB, HERE: (7 – AK) / 3 = AK / 5;
3 * AK = 35 – 5 * AK;
We transfer the known values to one side, and the unknown ones to the other side. When transferring values, their signs change to the opposite sign. That is, we get:
3 * AK + 5 * AK = 35;
AK * (3 + 5) = 35;
8 * AK = 35;
AK = 35/8.