Question

a) 5 x² + 3x + 5 = 0
b) x²+ 10x + 25 = 0
resolva as equações de segundo grau​

Answer 1

a)

$5x^2+3x+5=0\\\\5x^2+3x+5-5=0-5\\\\5x^2+3x=-5\\\\\frac{5x^2+3x}{5}=\frac{-5}{5}\\\\x^2+\frac{3x}{5}=-1\\\\\left(x+\frac{3}{10}\right)^2=-\frac{91}{100}\\\\x=-\frac{3}{10}+i\frac{\sqrt{91}}{10},\:x=-\frac{3}{10}-i\frac{\sqrt{91}}{10}$

b)

$x^2+10x+25=0\\\\x_{1,\:2}=\frac{-10\pm \sqrt{10^2-4\cdot \:1\cdot \:25}}{2\cdot \:1}\\\\x_{1,\:2}=\frac{-10\pm \sqrt{0}}{2\cdot \:1}\\\\x=\frac{-10}{2\cdot \:1}\\\\x=-5$