Linear Equations

When an amount was distributed among $$14$$ boys, each of them got Rs. $$80$$ more than the amount received by each boy when the same amount is distributed equally among $$18$$ boys. What was the amount?
The number of values of $$k$$ for which the system of equations $$x + y = 2$$, $$kx + y = 4$$, $$x + ky = 5$$ has only one solution is _________.
Show graphically that each one of the following systems of equations has infinitely many solutions:
Solve : $$\dfrac { z+9 }{ 3\left( z+5 \right)  } =-2$$
The greater of two numbers is 8 times the smaller and their sum is 180. Find the numbers.