Jawabanmu

2014-09-05T17:52:23+07:00
-a^2-4a+7= (20x^2+15x-25)-(4x^2-3)
-a^2-4a+7 = 20x^2+15x-25-4x^2+3
-a^2-4a+7 = 20x^2-4x^2+15x-25+3
-a^2-4a = 16x^2+15x-29


2014-09-05T17:54:55+07:00