Răspuns:
Explicație pas cu pas:
1.
a) x²+3x=0 ⇒ x(x+3)=0 ⇒ x1=0 x2=-3
b) 2x²-7x=0 ⇒x(2x-7)=0 ⇒x1=0 x2=7/2
c) 5x²+4x=0 ⇒x(5x+4)=0 ⇒x1=0 x2=-4/5
d) x²-9=0 (x-3)(x+3)=0 ⇒x1=3 x2=-3
2
a) x²+4x+3=0 ⇒(x+1)(x+3)=0 ⇒x1=-1 x2=-3
b) x²+7x+12=0 ⇒(x+3)(x+4)=0 ⇒x1=-3 x2=-4
c) x²-11x+24=0
x1,2=11±√121-4·24/2=11±5/2 x1=8 x2=3
d) 4x²+4x+3=4x²+4x+1+2=(2x+1)²+2=0 NU ARE SOLUTII REALE
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