Question

find the value of the following I power 7 plus I power 70 plus I power 12

Answer 1

Yes, you are right, we get x^2 by multiplying two x and the integer of remaining terms.

Like, in the above example if u follow regular multiplication, then you will multiply x of (x-1) and (x-2) and then -3 of (x-3), and you will get -3x^2.

Now in your problem, if you want to get x^9, you have to multiply in this way. and you will get —x^9 — 2x^9 — 3x^9 —…..—10x^9

so, the coefficient of x^9 is —1 — 2 — 3 — 4 ….—10= —55.