15х+60=12;
15х=12-60;
15х=-48/15;
х=-3,2
1.2x+5>4x-5
2x-4x>-5-5
-2х>-10
x<5
...............................................................................
B² -9 =(b -3)(b +3)
(2b +3(b +3)) /(b -3)(b +3) = (2b +3b +9) /(b -3)(b +3) =
(5b +9) / (b² -9)