Let's solve each equation step by step:

1) 5x - 7 * 5x - 2 = 90
First, apply the distributive property on the left side:
5x - 35x + 14 = 90
Combine like terms:
-30x + 14 = 90
Subtract 14 from both sides:
-30x = 76
Divide by -30:
x = -2.533

2) 3x + 1 + 3 = 210
Combine like terms on the left side:
3x + 4 = 210
Subtract 4 from both sides:
3x = 206
Divide by 3:
x = 68.667

3) 4x + 2/3 + 7 * 2x + 1 = 4
First, simplify the left side:
4x + 2/3 + 14x + 1 = 4
Combine like terms:
18x + 2/3 + 1 = 4
Combine constants:
18x + 2/3 + 3/3 = 4
18x + 5/3 = 4
Subtract 5/3 from both sides:
18x = 7/3
Divide by 18:
x = 7/54

Therefore, the solutions are:
x = -2.533, x = 68.667, x = 7/54 or approximately 0.130 quadratically.