Question

sabendo-se que -1 é a raiz da equação (m+5)x+3m=3x(x-2) e sendo k=2m quadrado -5,então k é igual a

Answer 1

$(m+5)x+3m=3(x-2)\\\\(m+5)x-3(x-2)+3m=0\\\\(m+5)\cdot(-1)-3[(-1-2)]+3m=0\\\\-m-5-3\cdot(-3)+3m=0\\\\-m-5+9+3m=0\\\\2m+4=0\\\\2m=-4\\\\m=-2\\\\k=2m^2-5\\\\k=2\cdot(-2)^2-5\\\\k=2.4-5\\\\k=8-5\\\\\boxed{k=3}\\\\LETRA\,\,B$