Решите 6 и 7, срочнооооооооо

25xˇ2-4 -(25xˇ2-10x+1)=4 10x-1=4,10x=5, x=1/2 100xˇ2-16 =( 10x)ˇ2 - 4ˇ2 = (10x+4)(10x-4)=4.(5x+2)(5x-2) 7)1/81aˇ2-0,09cˇ4 = (1/9.a)ˇ2 - (0,3cˇ2)ˇ2=(1/9a +0,3cˇ2)(1/9-0,3cˇ2) (b+8)ˇ2-4bˇ2 =  (b+8)ˇ2 - (2b)ˇ2= (b+8+2b)(b+8-2b)= =((3b+8)(8-b)