Question

Resolva:
A)X^2 -9=0
B)x^2-7x=0
C)2x^2-7x+3=0

Answer 1

Resposta:

- Formula ➳ X = - b ± √b² - 4 . a . c  / 2 . a

=========================== CÁLCULOS ===========================

A) x² - 9 = 0 ➳  a = 1 , b = 0 , c = -9

X = - b ± √b² - 4 . a . c  / 2 . a

X = - 0 ± √0² - 4 . 1 . (-9)  / 2 . 1

X = - 0 ± √0 - 4 . 1 . (-9)  / 2 . 1

X = - 0 ± √0 -  (-36)  / 2 . 1

X = - 0 ± √0 +  36  / 2 . 1

X = - 0 ± √36  / 2 . 1

X = - 0 ± 6  / 2 . 1

X = - 0 ± 6  / 2 ➳ X' = - 0 + 6 / 2 ➳ X' = 6 / 2 ➳ X' = 3

                       ➳ X" = - 0 - 6 / 2 ➳ X" = - 6 / 2 ➳ X" = - 3

➤ S = {3 , -3}

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B) x² - 7x = 0 ➳ a = 1 , b = -7 , c = 0

X = - b ± √b² - 4 . a . c / 2 . a

X = - (-7) ± √(-7)² - 4 . 1 . 0 / 2 . 1

X = - (-7) ± √49 - 4 . 1 . 0 / 2 . 1

X = - (-7) ± √49 - 0 / 2 . 1

X = - (-7) ± √49 / 2 . 1

X = - (-7) ± 7 / 2 . 1

X = 7 ± 7 / 2 ➳ X' = 7 + 7 / 2 ➳ X' = 14 / 2 ➳ X' = 7

                   ➳ X" = 7 - 7 / 2 ➳ X" = 0 / 2 ➳ X" = 0

➤ S = {7 , 0}

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C) 2x² - 7x + 3 ➳ a = 2 , b = -7 , c = 3

X = - b ± √b² - 4 . a . c / 2 . a

X = - (-7) ± √(-7)² - 4 . 2 . 3 / 2 . 2

X = - (-7) ± √49 - 4 . 2 . 3 / 2 . 2

X = - (-7) ± √49 - 24 / 2 . 2

X = - (-7) ± √25 / 2 . 2

X = - (-7) ± 5 / 2 . 2

X = 7 ± 5 / 4 ➳ X' = 7 + 5 / 4 ➳ X' = 12 / 4 ➳ X' = 3

                   ➳ X" = 7 - 5 / 4 ➳ X" = 2 / 4 ➳ X" = 1/2

➤ S = {3 , 1/2}

(ﾉ◕ヮ◕)ﾉ*:･ﾟ✧ Espero ter ajudado, Bons estudos ◕3◕