1) ((79+41)(79²-79*41+41²))/120-79*41=(79²-79*41+41²)-(79*41)=79²+41²=4560

2) a) 7b⁴-56b=7b(b³-8)=7b(b³-2³)

b) a⁴-12a³+48a²-64a=a³(a-12)+16a(3a-4)=

c) c²(c+4c)+2d(c+4c)=(c²+2d)(c+4c)=(c²+2d)5c