Jawabanmu

2014-09-09T21:40:22+07:00
1. (a+5) x (5a-1)
=a(5a-1) + 5(5a-1)
=5a² - a + 25a - 5
=5a² + 24a - 5

2. (7-2c) x (2c-7)
=7(2c-7) - 2c(2c-7)
=14c - 49 - 4c² + 14c
=4c² + 28c - 49
2014-09-09T21:57:02+07:00
(a+5)(5a-1) = 5a²-a+25a-5= 5a²+24a-5
(7-2c)(2c-7) = 14c-49-4c²+14c= 28c-4c²-49