Question

упростите выражение и решите 12 и 13

Answer 1

12.
(2x+5)²-(2x-3)*(2x+1)=4
4x²+20x+25-4x²-2x+6x+3=4
24x=-24  |÷24
x=-1.
13.
(b+1+1/(b-1)):(b²/(b²-2b+1)=((b+1)*(b+1)+1)/(b-1)):(b²/(b-1)²)=
=((b²-1)+1/(b-1)):(b²/(b-1)²))=(b²/(b-1)):(b²/(b-1)²)=b²*(b-1)²/(b²*(b-1))=b-1.