Show, where a and b are both integers, that if 13 | (3a + 5b), then 13 | (7a + 3b).
A number has 41 digits and is divisible by 7.
333...333(20 3s) x1 555...555(20 5s)
Find the value represented by x1
It is given 9 | 506mn78. The remainder is 2 when 506mn78 is divided by 8. Find the possible values of m and n
A 7-digit number , 1962mn6, is a multiple of 72 . Find the possible values of m and n.
a and b are both integers. Shown that if 7 | (a+b) and 7 | (3a-b), then 7 | (5a+b).