Question

Simplifique as expressões:
a) (x+7)(x-7)-x²+50
b) (4x+3)²-24x-9
c) (x-5)²+(x-3)²-16

Answer 1

a)
= (x + 7).(x - 7) - x² + 50

= x² - 7x + 7x - 49 - x² + 50

= x² - 49 - x² + 50

= 50 - 49

= 1

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b)
= (4x + 3)² - 24x - 9
= (4x)² + 2.3.4x + 3² - 24x - 9
= 16x² + 24x + 9 - 24x - 9
= 16x² + 24x - 24x + 9 - 9

= 16x²

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c)
= (x - 5)² + (x - 3)² - 16

= x² - 2.5x + 25 + x² - 2.3x + 9 - 16

= x² - 10x + 25 + x² - 6x + 9 - 16

= x² + x² - 10x - 6x + 25 + 9 - 16

= 2x² - 16x + 34 - 16

= 2x² - 16x + 18

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