4. Suppose that a positive integer is written in decimal notation as n = akak–1 … a2a1a0 where 0 ai 9. Prove that n is divisible by 11 if and only if the alternating sum of its digits a0 – ai + … + (–1) kak is divisible by 11.

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

=

side j'k'=distance between j' and k'

=

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl

sorry i just need to anwers this to get points

step-by-step explanation: