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.
It can't they have no common factor
200 milimeters is the answer
2 points=2%=0.02
205000×0.02=4,100 cost of 2 points
Closing costs is
4,100+450+575+600
=5,725....answer
Hope it helps!