A) Find a number

that solves the congruence

<span>.
</span>

means that 9x-9 is a multiple of 14,
<span>
that is 9(x-1) is a multiple of 14. A clear solution in the set is x=1
b) Find a number </span>

that solves the congruence

<span>.
</span>

means that 3x-4 is a multiple of 5,
<span>
x</span>∈{0, 1, 2, 3, 4} , so for these values 3x-4 becomes {-4, -1, 2, 5, 8}.
so x= 3 <span>
c)Find a number </span>

that solves the congruence

<span>.
</span>

means that 999x-998 is a multiple of 1,000<span>
we can check that for x=2, 999*2-998=1,998-998=1,000
d)Find a number </span>

that solves the congruence


means that 4x-17 is a multiple of 21,
fro x=7, 4x=28 and so 4x-17=28-17=21 is a multiple of 21.
Answers:
A) 1
B) 3
C) 2
D) 4