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ajutatima careva la ex 5 si 6

Ajutatima Careva La Ex 5 Si 6 class=

Răspuns :

Iakabcristina2
5a)(x+3)²=x²+6x+9
b)(x-5)(x+5)=x²-25

6a)ΔADE≈ΔABC=>AD/AB=DE/BC=AE/AC
3/7=2/AC=>AC=14/3=>EC=AC-AE=>EC=14/3-2
=>EC=(14-6)/3=8/3

b)AD²=BDxDC (t.inaltimii)
AD²=2x4=>AD²=8=>AD=2√2
AB²=BDxBC (t.catetei)
AB²=2x6=>AB²=12=>AB=2√3

c)BC²=AB²+AC² (t.Pitagora)
BC²=4+9=>BC=√13

d)Aria cercului=πr²=25π
Lungimea cercului=2πr=10π

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