What is the average of first 21 multiples of 2.1?

I. 6x² + 19x + 10 = 0

II. y² + 10y + 25 = 0

I. 9x² + 45x + 26 = 0

II. 7y² – 59y − 36 = 0

I. 99x² + 161 x + 26 = 0

II. 26 y² + 161 y + 99 = 0

I. 6x² - 13 x + 6 = 0

II. 15 y² + 11 y - 12 = 0

I. 2x² – 5x - 12 = 0

II. y² – 11y + 30 = 0

I. 18p²- 21p + 6 = 0      

II. 16q² - 24q +9 = 0

I. 4x² - 21x + 20 = 0

II. 8y² - 22y + 15 = 0

I. x² - (16)² = 0

II. 2y - 14 = 0

I. x² + 12√2 x + 22 = 0

II. y² - 13√2 y – 28 = 0

I. 2 x ² + x  – 1 = 0                 

II. 2 y ² - 3 y + 1 = 0