Let x,y $\in~Z^+$ such that 11|(3x+7y). Which of these must also be divisible by 11?

a. 4x+6y
b. x+y+5
c. 9x+4y
d. 4x - 9y
e. x+y-1

Question

Let x,y $\in~Z^+$  such that 11|(3x+7y).  Which of these must also be divisible by 11?

a. 4x+6y
b. x+y+5
c. 9x+4y
d. 4x - 9y
e. x+y-1

amistre64 · Answer

im confused as to why there would only be 1 correct choice

amistre64 · Answer

prolly seeing it a little off, might need to run a euclidean/reverse on it to be sure

amistre64 · Answer

7 = 3(2) + 1

                0
       0       1
0-2(1) = -2  ;  x' = -2,  y' = 1

11 * [3(-2)+7(1)=1]

3(-22)+7(11) = 11
    x''        y''

x = x'' + 7n
 y = y'' - 3n

primeralph · Answer

not surre too.........|dw:1369148376614:dw|