how can the orginal trinomial and your answer to help you determine the value of (10)(17)(11) without caculator

Question

This question is about trinomials and i dont get the question he is providing

 

Answer 1

you are leaving out information, however here is how to get the answer without a calculator...

(10)(17)(11)

when you multiply a 2-digit number by 11, split the digits and put the sum of the digits in between the two split digits

11*17

1   7, 1+7=8, 187 is the answer

now to multiply by 10 simply add a 0 at the end of the number, 10*187=1870

by the way, if the sum of the digits exceeds 9, do the following...

11*87=

8   7, 8+7=15, put the 5 between the 8 and 7 and add the 1 to the 8 to get 9, 957

11*79=7   9, 7+9=16, 869 is the answer