Question

Rozwiąz rownanie korzystajac z wzorów skroconego mnozenia.

a) (x+12 -=10

b)(x-5 - = 0

c)2 + 7 = (x+7 +

d)16-4 - x = (2 - 2x) ( 2x+2)

Answer 1

a)

(x+12)^2 -x^2 = 10

x^2 + 24x +144 -x^2 = 10

24x = 10 - 144

24x = - 134

x = -5 7/12 

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b)

(x-5)^2 - x^2 = 0

x^2 -10x + 25 - x^2 = 0

-10x = - 25

x = 2,5

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c)

2x^2 + 7 =(x+7)^2 + x^2

2x^2 + 7 = x^2 +14x + 49 + x^2

-14x = 49-7

-14x = 42

x = -3 

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d)

16 - 4x^2 - x =(2-2x)(2x+2)

16 - 4x^2 - x =(2-2x)(2+2x)

16 - 4x^2 - x = 4 - 4x^2

-x = 4 -16

-x = -12 x 

x = 12

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