Question

por meio da fórmula de Bhaskara resolva as seguintes equações:
x {}^{2} - 13x + 22 = 0x
2
−13x+22=0
7 {x}^{2} - 1x - 1 = 07x
2
−1x−1=0
{x}^{2} - x - 3 = 0x
2
−x−3=0
​

Answer 1

Resposta:

$a)\\ \\ x^{2} -13x+22=0\\ \\ x=\frac{-b+-\sqrt{b^{2}-4.a.c } }{2.a} \\ \\ x=\frac{13+-\sqrt{-13^{2}-4.1.22 } }{2} \\ \\ x=\frac{13+-\sqrt{169-88} }{2} \\ \\ x=\frac{13+-\sqrt{81} }{2} \\ \\ x=\frac{13+-9}{2} \\ \\ x'=\frac{13+9}{2} =\frac{14}{2} =7\\ \\ x''=\frac{13-9}{2} =\frac{4}{2} =2$

$b)\\ \\ 7x^{2} -1x-1=0\\ \\ x=\frac{-b+-\sqrt{b^{2}-4.a.c } }{2.a} \\ \\ x=\frac{1+-\sqrt{-1^{2}-4.a.c } }{2.7} \\ \\ x=\frac{1+-\sqrt{1-4.4.(-1)} }{14} \\ \\ x=\frac{1+-\sqrt{1+8} }{14} \\ \\ x=\frac{1+-\sqrt{9} }{14} \\ \\ x=\frac{1+-3}{14} \\ \\ x'=\frac{1+3}{14} =\frac{4}{14}=\frac{2}{7}\\ \\ x''=\frac{1-3}{14} =-\frac{2}{14} =-\frac{1}{7}$