if { x } is the product of all even integers from 1 to x inclusive , what is the greatest prime factor of { 14 } + { 12 } ?
"soln : { 14 } + { 12 } = 14 * { 12 } + { 12 } = 15 * { 12 } answer : c"
add(divide(add(14, 12), const_2), multiply(1, const_2))