Question

Audem PLEASE!
Como resolver a equação de 2 grau:
-7x²-6x+1=0

Answer 1

- 7x² - 6x + 1 = 0  (-1)
7x² + 6x - 1 = 0
a = 7
b = 6
c = -1
Δ = b² - 4ac
Δ = 6² - 4.7. (-1)
Δ = 36 + 28
Δ = 64
x = - b + - √Δ/2a
x = - 6 + - √64/ 2.7
x = - 6 + - 8 / 14
x' = 2/14 ⇒ x' = 1/7
x" = -14/14 ⇒ x" = - 1

S = { 1/7 ; - 1 }

Answer 2

$\text{a=-7 \ \ b=-6 \ \ c=1 } \\ \\ \frac{-b+- \sqrt{b^{2}-4*a*c } }{2*a} \\ \\ \frac{6+- \sqrt{-6^{2}-4*(-7)*1 } }{2*-7} \\ \\ \frac{6+- \sqrt{36+28 } }{-14} \\ \\ \frac{6+- \sqrt{64} }{-14} \\ \\ \frac{6+8}{-14} = \frac{14}{-14} =-1 \\ \\ \frac{6-8}{-14} = \frac{-2}{-14} =\frac{1}{7} \\ \\ S=\boxed{\boxed{-1 \ \ ; \ \ \frac{1}{7} }}}$