Question

poproszę o pomoc z zadaniami matematycznymi

Answer 1

Verified answer

Odpowiedź:

14.

7 x² - ( 5 + x)*(5 + 7 x) = 0

7 x² - ( 25 +35 x + 5 x + 7 x² ) = 0

7 x² - 25 - 40 x - 7 x² = 0

40 x = - 25 / : 40

x = - 0,625 = -  [tex]\frac{5}{8}[/tex]

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15.

p = 5 k

k = s - 5   ⇒  s = k + 5

więc

k + s  +  p = 21,80

k + ( k + 5 ) + 5 k = 21,80

7 k + 5 = 21,80 / - 5

7 k = 16,80  / : 7

k = 2,40

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p = 5*2,40 = 12,00

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s = 2,40 + 5 = 7,40

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Kubek kosztował 2,40 zł, pasta 12 zł, a szczoteczka 7,40 zł.

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16,

a)  [tex]k_{50} = 3*50 = 150[/tex]                    [tex]k_{49} = 3*49 = 147[/tex]

150 - 147 = 3

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b)  [tex]k_{g60} =3*60 = 180[/tex]               [tex]k_{o60} = 2*60 = 120[/tex]

180 =120 = 60

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17.

a)  s = ( 4*12 + 8*7 ) cm = ( 48 + 56 ) cm = 104 cm

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b)  h² +20² = 29²

h² = 841 - 400 = 441

h = [tex]\sqrt{441} = 21[/tex]

s = 6*20 + 3*21 = 120 + 63 = 183

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18.

c = 2π*r = π*d = 2π cm / : π

d = 2 cm

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Szczegółowe wyjaśnienie: