1) C² + c = 6
2) 9x² + 8 = 18x
3) 3x² - 12 = 0
4) 4x - 4x² = 0

To solve these equations:

1) C² + c = 6
One possible solution is c = 2 and C = 4, as 4² + 2 = 16 + 2 = 18

2) 9x² + 8 = 18x
Subtracting 18x on both sides gives:
9x² - 18x + 8 = 0
Dividing by 9 gives:
x² - 2x + 8/9 = 0
This equation can be solved using the quadratic formula

3) 3x² - 12 = 0
Dividing by 3 gives:
x² - 4 = 0
x² = 4
x = ±2

4) 4x - 4x² = 0
Dividing by 4 gives:
x - x² = 0
x(1 - x) = 0
x = 0 or x = 1

These are the possible solutions for each equation.