Question

y=x²+x-2 ??? me respondam por favor...

Answer 1

Use a fórmula de baskara, então fica:
y=x²+x-2
x²+x-2=0
Δ= b²-4.a.c
Δ= 1²-4.1.(-2)
Δ= 1+8
Δ= 9 então temos
y= -b+-√Δ/2.a
y=-1+-√9/2.1
y=-+-3/2
y=x¹= -1+3= 2/2=1
y=x²= -1-3= -4/2= -2

Answer 2

$y= x^{2} +x-2$

Fazendo y=0, temos:

$x^{2} +x-2=0\\\\ \Delta=b ^{2}-4ac\\ \Delta=1 ^{2}-4*1*(-2)\\ \Delta=1+8\\ \Delta=9$

$\boxed{x= \frac{-b\pm \sqrt{\Delta} }{2a}}\\\\\\ x= \frac{-1\pm \sqrt{9} }{2*1}~\to~x= \frac{-1\pm3}{2}~\to~\begin{cases}x'= \frac{-1+3}{2}~\to~x'= \frac{2}{2}~\to~x'=1\\\\ x''= \frac{-1-3}{2}~\to~x''= \frac{-4}{2}~\to~x''=-2 \end{cases}\\\\\\\\ \boxed{S=\{1,-2\}}$

Espero ter ajudado e tenha ótimos estudos =)