Explicație pas cu pas:
3x²-12=0
x²-4=0
x²=4
x= ± 2
x= -2
x= 2
x1= -2
x2 = 2
x²-7x-18=0
x² + 2x-9x-18=0
x ×(x+2)-9(x+2)=0
(x+2)×(x-9)=0
x+2=0
x-9=0
x= -2
x=9
x1= -2
x2= 9
2x²-5x=0
x ×(2x-5)=0
x=0
2x-5=0
x=0
x= 5\2
x1=0
x2= 5\2
(formular alternativ)
x1 =0
x2= 2,5
3x³-x+2=0
3x³+3x²-3x²-3x+2x+2=0
3x²× (x+1)-3x ×(x+1) +2(x+1)=0
(x+1)×(3x²-3x+2)=0
x+1=0
3x²-3x+2=0
x=-1
x apartine lui R
Soluţia x= -1
