Question

Rezolvaţi următoarele ecuaţii :

$3 x^{2} -6x = 0 ; -2 x^{2} - 4x = 0 ; x^{2} -7x=0 ; -4 x^{2} +100=0 ;$
$10 x^{2} -x = 0 ; 4 x^{2} -9x=0 ; -7 x^{2} +14x=0 ; 14 x^{2} -2x=0 ; 2 x^{2} - x \sqrt{2}$

Answer 1

1. 3x²-6x=0 -> Dai factor comun pe 3x=> 3x(x-2)=0 => 3x=0=> x=0 si x-2=0 =>x=2
2. -2x²-4x=0=> -2x(x+2)=0 => -2x=0 =>x=0 si x+2=0 => x=-2
3. x²-7x=0 => x(x-7)=0 => x=0 si x-7=0 => x=7
4. -4x²+100=0 -> imparte prin 4 => -x²+25=0 -> inmulteste cu -1 =>x²-25=0 =>x²=25 => x=-5 si x=+5
5. 10x²-x=0 =>x(10x-1)=0 => x=0 si 10x-1=0 =>10x=1 =>x=1/10=0,1
6. 4x²-9x=0 =>x(4x-9)=0 => x=0 si 4x-9=0 =>4x=9 =>x=9/4=2,25
7. -7x²+14x=0 =>-7x(x-2)=0 => -7x=0=>x=0 si x-2=0=>x=2
8. 14x²-2x=0 =>2x(7x-1)=0 => 2x=0=>x=0 si 7x-1=0=>7x=1=>x=1/7
9. 2x²-x√2=0 => x(2x-√2)=0=>x=0 si 2x-√2=0=>2x=√2=>x=√2/2
/ - inseamna impartit (pentru fractie)