(5х-9)(5х+9)-25х^2-4х-19 при х=100

[latex](5x-9)(5x+9)-25x^2-4x-19 =[/latex] [latex]=25x^2 + 45x -45x -81-25x^2-4x-19=[/latex] [latex]= -4x -100=-4*100-100=-400-100=-500[/latex] Второй способ [latex](5x-9)(5x+9)-25x^2-4x-19 =[/latex] [latex]=(5x)^2 -9^2-25x^2-4x-19=[/latex] [latex]= -4x -100=-4*100-100=-400-100=-500[/latex]