Question

x2-3x-4=0 com a fórmula de bhaskara

Answer 1

x² - 3x - 4 =0

a=1
b=-3
c=-4

$\Delta=b^2-4ac \\ \Delta=(-3)^2-4(1)(-4) \\ \Delta=9+16 \\ \Delta=25 \\ \\ x= \frac{-b\pm \sqrt{\Delta} }{2a} =~~ \frac{-(-3)\pm \sqrt{25} }{2} =~~ \frac{3\pm5}{2} \\ \\ x'= \frac{3+5}{2} = \frac{8}{2} =4 \\ \\ x"= \frac{3-5}{2} =- \frac{2}{2} =-1 \\ \\ S=\{-1,4\}$