10. Infinitely many solutions:

Simplify this equation:

When
the equation becomes

This equality is true for all x, thus the equation has infinitely many solutions.
11. The equation
should have one solution x=-1.
First, simplify the equation:

This equation will have solution x=-1 when

Therefore, the initial equation is

12. The equation
should have infinitely many solutions.
Simplify it:

When
this equation will have infinitely many solutions.
Answer:
y= 2-2x
Step-by-step explanation:
Isolate y.

This would be 10-2 which would equal 8
6 + 9y - 18 = -3 Combine like terms (6 and -18)
9y - 12 = -3 Add 12 to both sides
9y = 9 Divide both sides by 9
y = 1