Question

If 8 is added to twice a number and this sum is multiplied by 3ˏ the result is the number multiplied by 3 and 9 is added to the product.Whats the number?
        

Answer 1

$n-a\ number\\\\(8+2n)\cdot3=3n+9\\\\8\cdot3+2n\cdot3=3n+9\\\\24+6n=3n+9\ \ \ \ /-24\\\\24-24+6n=3n+9-24\\\\6n=3n-15\ \ \ \ /-3n\\\\6n-3n=3n-3n-15\\\\3n=-15\ \ \ \ /:3\\\\3n:3=-15:3\\\\n=-5$