Answer: 26a2+30ac−40c2
Step-by-step explanation:
(5a+3c)(5a+3c)−(7c−a)(7c+a)
(5a)(5a)+(5a)(3c)+(3c)(5a)+(3c)(3c)+a2+−49c2
=25a2+15ac+15ac+9c2+a2+−49c2
25a2+15ac+15ac+9c2+a2+−49c2
=(25a2+a2)+(15ac+15ac)+(9c2+−49c2)
=26a2+30ac+−40c2
answer: 26a2+30ac−40c2
i hope it's help!
