N(x)= -0.4x^2 + 11.2x +10 solve for x
eschewing decimals,
-4x^2 + 112x + 100 = 0
x^2 - 28x - 25 = 0
the good ole quadratic formula reveals that x = 14 ± √221 = -0.866 or 28.866
-4x^2 + 112x + 100 = 0
x^2 - 28x - 25 = 0
the good ole quadratic formula reveals that x = 14 ± √221 = -0.866 or 28.866