Question

a √5x+4=3 b√x=x-6 c3√2x+4=2

Answer 1

a)
$\sqrt{5x+4}=3 \rightarrow 5x+4=9 \rightarrow 5x=5 \rightarrow x=1$

b)
$\sqrt x=x-6\rightarrow x=(x-6)^2 \rightarrow x=x^2 -12x +36$
$x=x^2 -12x +36 \rightarrow x^2-13x+36=0$
Calculando o discriminante:
$\Delta=(-13)^2-4.1.36=169-144=25$
Calculando x:
$x=\frac{13+-\sqrt{25}}{2}=\frac{13+-5}{2}\rightarrow x_1=4 \ \ e \ \ x_2=9$

c)
$\sqrt{2x+4}=2\rightarrow 2x+4=4 \rightarrow 2x=0 \rightarrow x=0$