Question

Equação do segundo grau completa:
1) x² - 3x = 0


2) 4x² = -16x


3) x² - 5x = -4x² - 2x

Answer 1

Coloque o 'x' em evidência:

$1) x^{2} -3x=0\\\\ x(x-3)=0\\\\ x=0\\\\x-3=0\to x=3\\\\ S=(0;3)$





$2)4 x^{2} =-16x\to 4 x^{2} +16x=0\\\\ x(4x+16)=0\\\\ x=0\\\\ 4x+16=0\to 4x=-16\to x= \frac{-16}{4} \to x=-4\\\\ S=(-4;0)$





$3) x^{2} -5x=-4 x^{2} -2x\to x^{2} -5x+4 x^{2} +2x=0\to 5 x^{2} -3x=0\\\\ x(5x-3)=0\to x=0\\\\ 5x-3=0\to 5x=3\to x= \frac{3}{5} \\\\ S=(0; \frac{3}{5})$