1)75xˇ2-12 = 3.(25xˇ2 -4) = 3.(5x+2)(5x-2)
2)-xˇ2-10x-25 = -(xˇ2 + 10x +25) = -(x+5)(x+5) = -(x+5)ˇ2
3)(6a+1)ˇ2 - 36aˇ2 = (6a+1)ˇ2 - (6a)ˇ2 =
= (6a+1+6a)(6a+1-6a)=(12a+1).1 = 12a+1
4)9xˇ3+6xˇ2+x=0
x.(9xˇ2 +6x +1)=0
x.(3x+1)(3x+1)=0, x=0, x= -1/3
5)225xˇ2-49=0, (15x)ˇ2 - 7ˇ2=0. (15x+7)(15x-7)=0
x= -7/15, x= 7/15
6)aˇ2 -10ab+25bˇ2- cˇ2 = (a-5)ˇ2 - cˇ2 = (a-5+c)(a-5-c)