Question

gente , alguém me ajuda , sou péssima em matematica !​

Answer 1

Resposta:

A)x

2

−8x+15=0

\frac{-b \pm \sqrt{-b^2 -4*a*c}}{2*a}

2∗a

−b±

−b

2

−4∗a∗c

a=1b=−8c=15

Vamos encontrar o Δ:

Δ=b2−4ac

Δ=(−8)2−4*(1)*(15)

Δ=64−60

Δ=4

\begin{gathered}x = \frac{-b \pm \sqrt{\triangle}}{2*a} \\ \\x = \frac{-(-8) \pm \sqrt{4}}{2*1} \\ \\ x = \frac{8 \pm2}{2} \\ \\ x' = \frac{8 +2}{2} \\ \\ x' = \frac{10}{2} \\ \\ x' = 5 \\ \\ \\ x ''= \frac{8 -2}{2} \\ \\ x' = \frac{6}{2} \\ \\ x'' = 3\end{gathered}

x=

2∗a

−b±

△

x=

2∗1

−(−8)±

4

x=

2

8±2

x

′

=

2

8+2

x

′

=

2

10

x

′

=5

x

′′

=

2

8−2

x

′

=

2

6

x

′′

=3