1
(x²+2x-63)/(49-x²(=((x²-7x)+(9x-63))/(49-x²)=(x(x-7)+9(x-7))/(49-x²)=
=(x-7)(x+9)/(7-x)(7+x)=-(x+9)/(x+7)
2
A)(4a/[(a-1)(a+1)]+(a-1)/(a+1)=(4a+(a-1)²)/(a²-1)=(4a+a²-2a+1)/(a²-1)=
(a²+2a+1)/(a²-1)=(a+1)²/[(a-1)(a+1)]=(a+1)/(a-1)
Б)
1)1/(3p-1)(9p²+3p+1)*(1+3p+9p²)/(1+3p)=1/((3p-1)(3p+1)
2)1/2(1-3p)-1/(1-3p)(1+3p)=(1+3p-2)/(1-3p)(1+3p)=(3p-1)/(1-3p)(1+3p)=
=-1/(1+3p)
3)2(1+3p)/3*(-1/(1+3p))=-2/3