Question

determine a solução das equações a seguir.

a) x²+5x-6=0
b) x²+10x+9=0​

Answer 1

$x^2+10x+9=0\\\\x_{1,\:2}=\frac{-10\pm \sqrt{10^2-4\cdot \:1\cdot \:9}}{2\cdot \:1}\\\\x_{1,\:2}=\frac{-10\pm \:8}{2\cdot \:1}\\\\x_1=\frac{-10+8}{2\cdot \:1}=-1,\:x_2=\frac{-10-8}{2\cdot \:1}=-9\\\\S(-1,-9)$

$x^2+5x-6=0\\\\x_{1,\:2}=\frac{-5\pm \sqrt{5^2-4\cdot \:1\cdot \left(-6\right)}}{2\cdot \:1}\\\\x_{1,\:2}=\frac{-5\pm \:7}{2\cdot \:1}\\\\x_1=\frac{-5+7}{2\cdot \:1}=1,\:x_2=\frac{-5-7}{2\cdot \:1}=-6\\\\S(1,-6)$