Question

Ajutor la acest atașament

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Answer 1

I.

x²=7

x = ±√7 => x=√7 ; x=-√7

2x²=98

x² = 49

x=√49

x=7

x²+2=0

x²=-2

x = ±√2 (faci ca in primul ex.)

II.

69-5(x-2)²=24

69 - 5(x²-2*x*2+2²)=24

69 - 5(x²-4x+4)=24

69 - 5x²+20x-20=24

49-5x²+20x=24

-5x²+20x=24-49

-5x²+20x = 25

-5x²+20x-25=0 | :5

-x²+4x-5=0 / *(-1)

x²-4x-5=0

x² x+(-5x) -5=0

x(x+1) -5(x+1)=0

(x+1)(x-5)=0

x+1=0

x=-1

x-5=0

x=5

S:{-1;5}