Question

(URGENTE)Seja f : R → R definida por f(x) = (2x+1)(x−3). Determine o(s) elemento(s) do dom´ınio cuja imagem ´e -5.

Answer 1

$\large\boxed{\begin{array}{l}\sf f(x)=\dfrac{2x+1}{x-3}\\\\\sf f(x)=-5\\\sf\dfrac{2x+1}{x-3}=-5\\\\\sf 2x+1=-5x+15\\\sf 2x+5x=15-1\\\sf 7x=14\\\sf x=\dfrac{14}{7}\\\\\sf x=2\end{array}}$