Liam's bookstore sold 40 notebooks and 20 newspapers for a total of $130. a day later, the bookstore sold 8 notebooks and 4 newspapers at the same prices, for a total of $28. how much does a notebook and a newspaper cost at liam's bookstore?

 the answer will be $2 each 2x12=28

Let x = price of 1 notebook ($)
let y = price of 1 newspaper ($)
Solving method : Elimination
1st step : write the system of equation
40x + 20y = 130
8x   + 4y   = 28

2nd step : make the variables equal to each other
-5(8x   + 4y  ) =( 28)(-5)
-40x - 20y = -140
3rd step : add the equations
       40x + 20y = 130
+    -40x - 20y = -140

                   0  = -10   
        
Answer : No solution