What is the value of the expression a) 12(3+13)= 192
b) 12(3+4+5+...+12+13)= 1,056
c) 12(1+2+3+...+12+13)= 1,092
d) 12(3)•12(13)= 5,616

Sandy is upgrading her internet service. fast internet charges $20 for installation and $52.45 per month. quick internet has free installation but charges $57.45 per month. part 1 out of 2 complete the equation that can be used to find the number of months after which the internet service would cost the same. use the variable x to represent the number of months of internet service purchased.