Question

Resolva as equações do 2 grau, sendo U=IR
\begin{lgathered}a) \\ {x }^{2} - 7 \times = 0 \ \\ \\ b) \\ {x}^{2} + 5x = 0 \\ \\ c) \\ 4 {x}^{2} - 9x = 0 \\ \\ d) \\ 3 {x}^{2} + 5x = 0\end{lgathered}a)x2−7×=0 b)x2+5x=0c)4x2−9x=0d)3x2+5x=0​ 

Answer 1

Resolva as equações do 2 grau, sendo U=IR

\begin{lgathered}a) \\ {x }^{2} - 7 \times = 0 \ \\ \\ b) \\ {x}^{2} + 5x = 0 \\ \\ c) \\ 4 {x}^{2} - 9x = 0 \\ \\ d) \\ 3 {x}^{2} + 5x = 0\end{lgathered}

equação do 2º grau INCOMPLETA (2 raizes)

a)x2−7×=0

x² - 7x = 0

x(x - 7) = 0

x = 0

e

(x - 7) = 0

x - 7 = 0

x = + 7

assim

x' = 0

x'' = 7

b)x2+5x=0

x² + 5x = 0

x(x + 5) = 0

x = 0

e

(x + 5) = 0

x + 5 = 0

x = - 5

assim

x' = 0

x'' = - 5

c)4x2−9x=0

4x² - 9x = 0

x(4x - 9) = 0

x = 0

e

(4x - 9) = 0

4x - 9 = 0

4x = + 9

x = 9/4

assim

x' = 0

x'' = 9/4

d)3x2+5x=0​

3x² + 5x = 0

x(3x + 5) = 0

x = 0

e

(3x + 5) = 0

3x + 5 = 0

3x = - 5

x = - 5/3

assim

x' = 0

x'' = -5/3