Question

7ª Questão: Simplifique as expressões abaixo:
a) (x − 5).(x − 6) − (x − 2).(x − 3)=
b) (−2 x+ 5).(6x° + 4 x+ 3 )=

c) (−3 x°+ 5x− 8) + (6x°− 4x− 3) =

Answer 1

a)
= (x − 5).(x − 6) − (x − 2).(x − 3)
= x² - 6x - 5x + 30 - (x² - 3x - 2x + 6)
= x² - 11x + 30 - (x² - 5x + 6)
= x² - 11x + 30 - x² + 5x - 6
= x² - x² - 11x + 5x + 30 - 6
= - 6x + 24
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b)
= (− 2x + 5).(6x² + 4x+ 3 )
= ( - 2x).(6x²) - 2x.4x - 2x.3 + 5.6x² + 5.4x + 5.3
= - 12x³ - 8x² - 6x + 30x² + 20x + 15
= - 12x³ - 8x² + 30x² - 6x + 20x + 15
= - 12x³ + 22x² + 14x + 15
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c)
= (−3 x² + 5x − 8) + (6x² − 4x − 3)
= - 3x² + 5x - 8 + 6x² - 4x - 3
= - 3x² + 6x² + 5x - 4x - 8 - 3
= 3x² + x - 11