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a fost răspuns

20 puncte! Cum se rezolva ecuatia: [tex]2x ^{2}+7x-4=0[/tex]


Răspuns :

Andrasamara
2x²+7x-4=0
Δ=49+32=81
√Δ=9
x1= (-7+9)/4=1/2
x2=(-7-9)/4=-4

Nitugheorghe57
2x²+7x-4=0⇒
a=2
b=7
c=-4
d=b²-4ac⇒d=(7)²-4×2×(-4)⇒d=49+32⇒d=81⇒√d=√81⇒d=9
x1x2=-b+-√d/2a
x1=-7+9/2×2⇒2/4⇒x1=1/2
x2=-7-9/4⇒-16/4⇒x2=-4
succes