We start by completing the square of the left-hand side,
y2+3y+4=y+232−232+4=y+232−49+416=y+232+47.
The equation is then
y+232+47=0.
The first term y+232 is always greater than or equal to zero because it is a square and 47 is a positive number. This means that the left hand side cannot be zero, regardless of how y is chosen. The equation has no solution.