1.(5a - 12b)(5a + 12b)=
2.(6a + 5b)²=
3.(8a - b)²=
4.(а + 3)(а² - 3а +9)=
5. (b - 2)(b²+ 2b +4)=
6.(- a² + 9)(a² + 9)=
7.(a⁸ + b ⁸)(a⁴ + b ⁴)(a⁴- b ⁴)=

(5a-12b)(5a+12b)= (5a-12b)*5a+(5a-12b)*12b= 25a²-60ab+60ab-144b²=25a-144b²

Наверное я не права

1)(5a-12b)(5a+12b)= (5a-12b)*5a+(5a-12b)*12b= 25a²-60ab+60ab-144b²=25a-144b² 2)(6а+5b)²= 6²a²+5²b² 3)(8a-b)²=8²a²-b² 4)(а + 3)(а² - 3а +9)= (а+3)*a²+(a+3)*(-3a)+(a+3)*9=a³+3a²-3a²-9a+9a+27=a³+27 5) (b - 2)(b²+ 2b +4)=(b-2)*b²+(b-2)*2b+(b-2)*4=b³-2b²+2b³+4b+4b-8=3b³-2b²+8b 6.(- a² + 9)(a² + 9)=(-a²+9)*a²+(-a²+9)*9=-a⁴+9a²-9a+81=-a⁴+81