x=-9/4 \\ npu\ x<-9/4\ y\,'<0; \\ npu\ x>-9/4\ y\,'>0 => \\ y(-9/4)=y_{min}(x) \\ y_{min}(x) = 81/4 + 18/4+83 = 107\frac{1}{4}\ " alt="y=4x^2+18x+83 \\ y\,'= 8x+18 \\ y\,'=0 <=> x=-9/4 \\ npu\ x<-9/4\ y\,'<0; \\ npu\ x>-9/4\ y\,'>0 => \\ y(-9/4)=y_{min}(x) \\ y_{min}(x) = 81/4 + 18/4+83 = 107\frac{1}{4}\ " align="absmiddle" class="latex-formula">