x³-7x²-3x+21=0 x²(x-7)-3(x-7)=0 (x+√3)(x-√3)(x-7)=0 x³-7x²-4x+28=0 x²(x-7)-4(x-7)=0 (x+2)(x-2)(x-7)=0 x³+3x²+x+3=0 x²(x+3)+(x+3)=0 (x²+1)(x+3)=0 3x³+6x²-9x-18=0 3x²(x+2) -9(x+2)=0 (x√3+3)(x√3-3)(x+2)=0 x³+3x²-5x-15=0 x²(x+3) -5(x+3)=0 (x+√5)(x-√5)(x+3)=0 x³+x²+x+1=0 x²(x+1)+(x+1)=0 (x²+1)(x+1)=0
a)xdo 3-7x^-3x+21=0 x³-7x²-3x+21=0 x²(x-7)-3(x-7)=0 (x-7)(x²-3)=0 (x-7)(x²-√3²)=0 korzystamy ze wzoru a²-b²=(a-b)(a+b) (x-7)(x-√3)(x+√3)=0 _______________________________ b)xdo3-7x^-4x+28=0 x³-7x²-4x+28=0 x²(x-7)-4(x-7)=0 (x-7)(x²-4)=0 (x-7)(x²-2²)=0 (x-7)(x-2)(x+2)=0 _______________________ c)xdo3+3x^+x+3=0 x³+3x²+x+3=0 x²(x+3)+1(x+3)=0 (x+3)(x²+1)=0 _______________________ d)3xdo3+6x^-9x-18=0 3x³+6x²-9x-18=0 3x²(x+2)-9(x+2)=0 (3x²-9)(x+2)=0 3(x²-3)(x+2)=0 3(x-√3)(x+√3)(x+2)=0 __________________________ e)xdo3+3x^-5x-15=0 x³+3x²-5x-15=0 x²(x+3)-5(x+3)=0 (x+3)(x²-5)=0 (x+3)(x²-√5²)=0 (x+3)(x-√5)(x+√5)=0 __________________________ f)xdo3+x^+x+1=0 x³+x²+x+1=0 x²(x+1)+1(x+1)=0 (x+1)(x²+1)=0 _____________________________________________________
