Question

Calcule as equações de segundo grau
A) -x²+3x+4=0

Answer 1

Resposta:

Explicação passo-a-passo:

temos:

-x²+3x+4=0

aplicando Baskara temos:

x=( -b+-V b²-4ac)/2a

x=(-3+-V3²-4*-1*4)/-2

x=(-3+-V9+16)/-2

x=(-3+-V25)/-2

x=(-3+-5)/-2

x'=(-3+5)/-2

x'=2/-2

x'= -1

x''=(-3-5)/-2

x''=-8/-2

x''=4

daí:

x'= -1

x''=4

Answer 2

$\boxed{\textcolor{purple}{\Delta={3}^{2}-4.( - 1).(4)}} \\ \boxed{\textcolor{purple}{\Delta=9 + 16}} \\ \boxed{\textcolor{purple}{\Delta=25}}$

$\boxed{\textcolor{cyan}{x=\frac{-b±\sqrt{\Delta}}{2a}}} \\ \boxed{\textcolor{cyan}{x=\frac{-3±\sqrt{25}}{2( - 1)}}}$

$\boxed{\textcolor{blue}{x=\frac{-3±5}{ - 2}}}$

$\boxed{\textcolor{orange}{x'=\frac{-3 + 5}{ - 2} = \frac{2}{ - 2} = - 1 }}$

$\boxed{\textcolor{green}{x''=\frac{-3 - 5}{ - 2} = \frac{ - 8}{ - 2} = 4 }}$

$s=\left\{(\textcolor{orange}{-1},\textcolor{green} {4})\right\}$