To solve this system using the substitution method, we can start by solving one equation for one variable and then substituting that expression into the other equation.
Let's solve the first equation for x:
2x + 3y = 4
2x = 4 - 3y
x = (4 - 3y)/2
Now we substitute this expression for x into the second equation:
-4x - 6y = -8
-4((4 - 3y)/2) - 6y = -8
-2(4 - 3y) - 6y = -8
-8 + 6y - 6y = -8
-8 = -8
The equation simplifies to -8 = -8, which is a true statement. This means that the two equations are equivalent and have an infinite number of solutions.
So the answer is: infinite solutions.