1 Упростите выражения: a) (3 - a)(3 + a); 6) (b2aX2a - b); в) (x* - 1)(1 + x²). 2 a) (a - 4)(a - 4); G) (5x + g)(y - 5x); H) (1 - x^)(x + 1).​

\bf (3-a)(3+a)=3^2-a^2=9-a\\\\\left ( x^2-1 \right )\left ( 1+x^2 \right )=\left ( x^2-1 \right )\left ( x^2+1 \right )=x^4-1\\\\(a-4)(a-4)=(a-4)^2=a^2-8a+16\\\\(5x+y)(y-5x)=(y+5x)(y-5x)=y^2-25x^2\\\\(1-x)(x+1)=(1-x)(1+x)=1-x^2