Solve the given equations and answer the following questions.

I. x² - (a + 23)x + 18a + 88 = 0 

II. y² - (b + 13)y + 12b + 12 = 0

III .z² + (a + b)z + (P² × 2) = 0

Note:

i)one of the roots of equation I is 19. The other root of equation I is equal to one of the roots of equation II.

ii) one of the root of equation III is by solving the given simplification: 

iii) 25% of 120 - (12 × 5) + 350/7 + z = (- 60/12)