Question

Usando a fórmula de Báskara calcule as raízes da seguinte equação:

2x(x+5)=x-7

Answer 1

$2x(x+5)=x-7\to \\\\2 x^{2} +10x-x+7=0\to\\\\ 2 x^{2} +9x+7=0\\\\ a=2;b=9;c=7\\\\\\ \Delta=b^2-4ac\to \Delta=9^2-4*2*7\to \Delta=81-56\to \Delta=25\\\\ x' \neq x''\\\\\\ x= \frac{-b\pm \sqrt{\Delta} }{2a} \to x= \frac{-9\pm \sqrt{\Delta25} }{2*2} \to x= \frac{-9\pm 5}{4} \to \\\\\\ x'= \frac{-9+ 5}{4} \to x'= \frac{-4}{4} \to x'=-1\\\\\\ x''= \frac{-9-5}{4} \to x''= \frac{-14}{4} \to x= \frac{-7}{2} \\\\\\\\ S= \left \{\frac{-7}{2};-1 \left \}$

Answer 2

2x(x+5) = x -7
2x^2+10x-x+7=0
2x^2+9x+7=0
∆= 25
x= -9+-5/4
x,= -9+5/4= -4/4 = -1
x,,= -9-5/4= -14/4 simplifica por 2 = -7/2

espero ter ajudado!