Question 430099
-15x+3y=6_y=2+5x

Replace all occurrences of y with the solution found by solving the last equation for y.  In this case, the value substituted is 5x+2.
-15x+3(5x+2)=6_y=5x+2

Multiply 3 by each term inside the parentheses.
-15x+15x+6=6_y=5x+2

Since -15x and 15x are like terms, subtract 15x from -15x to get 0.
0+6=6_y=5x+2

Remove the 0 from the polynomial; adding or subtracting 0 does not change the value of the expression.
6=6_y=5x+2

Since 6=6, the equation will always be true.
Always True_y=5x+2