1. c(a-c)-(a-c)·3= c×(a-c)-3(a-c)= (a-c)(c-3)
2. 3c·(a-c)= 3ac-3c×c= 3ac-3c²
3. (c+3)(a-c)= c(a-c)+3(a-c)= ac-c²+3a-3c
4. (c-3)(a-c)= c(a-c)-3(a-c)= ac-c²-3a-3c
5. (c-3)(a+c)= ac+c×c-3a-3c= ac+c²-3a-3c
1. c(a-c)-(a-c)·3= c×(a-c)-3(a-c)= (a-c)(c-3)
2. 3c·(a-c)= 3ac-3c×c= 3ac-3c²
3. (c+3)(a-c)= c(a-c)+3(a-c)= ac-c²+3a-3c
4. (c-3)(a-c)= c(a-c)-3(a-c)= ac-c²-3a-3c
5. (c-3)(a+c)= ac+c×c-3a-3c= ac+c²-3a-3c