Answer:
1. One solution
2. No solution
3. No solution
4. Infinitely many solutions
Explanation:
1. 5x + 6 = 2 + 3x
2x = -4
x = -2
One solution
2. 2 (6 - 2y) = -1 (4y - 9)
12 - 4y = -4y + 9
12 ≠ 9
No solution
3. 5x + 1 = 4x - 3 + 1x
1 ≠ -3
No solution
4. 2x - 6 = 2 (x + 2) - 10
2x - 6 = 2x + 4 - 10
-6 = -6
Infinitely many solutions