the function y = ax^2 + bx + c

a<0 has is maximum equal to c - b^2/(4a)

a>0 has is minimum equal to c - b^2/(4a)

f(x)=1.2x^2+5.8x+3.7

a = 1.2, b = 5.8, c = 3.7

a>0 follows the function has minimum

f min = 3.7 - 5.8^2/(4*1.2)

f min = -3.31

click here to see the graph of the function