ANSWER: 2790A
Step-by-step explanation: 90,\:5,\:31 =2\cdot \:45 45\:\mathrm{divides\:by}\:3\quad \:45=15\cdot \:3 =2\cdot \:3\cdot \:15 15\:\mathrm{divides\:by}\:3\quad \:15=5\cdot \:3 =2\cdot \:3\cdot \:3\cdot \:5 2,\:3,\:5\mathrm{\:are\:all\:prime\:numbers,\:therefore\:no\:further\:factorization\:is\:possible} =2\cdot \:3\cdot \:3\cdot \:5 =2\cdot \:3\cdot \:3\cdot \:5\cdot \:31 \mathrm{Multiply\:the\:numbers:}\:2\cdot \:3\cdot \:3\cdot \:5\cdot \:31=2790 =2790 \mathrm{Compute\:an\:expression\:comprised\:of\:factors\:that\:appear\:in\:at\:least\:one\:of\:the\:factored\:expressions} =2790A