2022/012) For integers x and y 34x = 43 y show that x + y is composite

 We have 34x + 34 y = 43 y + 34 y = 77 y

so 34(x+y) = 77 y

or $x+ y = \frac{77 * y}{34}$

34 is coprime to 77 , x+ y is integer so $\frac{y}{34}$ is integer  

$x+y = 77 * \frac{y}{34}$ has a factor 77 and 77 is composite so x + y is composite