Waecmaths

Title waecmaths question
Question 1

If $\{x:2\le x\le 18;x\in integer\}$and 7 + x = 4(mod 9). Find the highest value of x

Question 4

Fig1 and Fig 2are the addition and multiplication tables respectively in modulo 5. Use the these tables to solve the equation $(n\otimes 4)\oplus 3=0(\bmod 5)$