Answer:
[tex]-10a^2+25ab-15ac+12a+12b-2c[/tex]
Step-by-step explanation:
[tex](7a+5b-2c)+(5a+7b)+(2a-7c)+(2a-5b+3c)[/tex]
Distribute:
[tex]=7a+5b-2c+5a+7b+(2a)(2a)+(2a)(-5)+(2a)(3c)+(-7a)(2a)+(-7a)(-5b)+(-7a)(3c)[/tex]
[tex]=7a+5b-2c+5a+7b+4a^2-10ab+6ac-10a^2+35ab-21ac[/tex]
Combine all like terms:
[tex]=(4a^2-14a^2)+(-10ab+35ab)+(6ac-21ac)+(7a+5a)+(5b+7b)+(-2c)[/tex]
[tex]=-10a^2+25ab-15ac+12a+12b-2c[/tex]
