Question

x² + x (2x - 15) = 0

Answer 1

$x^{2} + x (2x - 15) = 0 \\ \\ x^{2} +2 x^{2} -15x \\ \\ 3 x^{2} -15x = 0$


Resolvendo por Bháskara

a=3,b=-15,c=0
Δ=b2−4ac
Δ=(-15)2−4*(3)*(0)
Δ=255+0
Δ=255

$x = \frac{-0 \pm \sqrt{144}}{2*1} \\ \\ x = \frac{-(-15) \pm \sqrt{255}}{2*3} \\ \\ x = \frac{15 \pm {15}}{6} \\ \\ x' = \frac{15 + 15}{6} \\ \\ x' = \frac{30}{6} \\ \\ x' = 5 \\ \\ \\ x'' = \frac{15-15}{6} \\ \\ x'' = \frac{0}{6} \\ \\ x' = 0$

S = {5, 0}