The first system of equations has infinite solutions because you can write one equation as a linear combination of the other.The second system of equations has no solution because mathematically an incoherence results -14 = -2 / 7I attach the solutions for greater understanding.
x-4y=12; 5x-20y=60 --> infinitely many
y-7x=-14; 7y-49x=-2 --> none
x-4y=12; 5x-20y=60 --> infinitely many
y-7x=-14; 7y-49x=-2 --> none