Question

calcule o valor de x nas figuras

Answer 1

$\frac{x+6}{3x} = \frac{x}{x+3} \\ \\ 3x^2=(x+6)(x+3) \\ \\ 3x^2=x^2+3x+6x+18 \\ \\ 3x^2-x^2-3x-6x-18=0 \\ \\ 2x^2-9x-18=0 \\ \\ \Delta=(-9)^2-4(2)(-18) \\ \\ \Delta=81+144 \\ \\ \Delta= 225 \\ \\ x= \frac{9~\pm~15}{4} \\ \\ x'= \frac{9~+~15}{4} =6 \\ \\ x''= \frac{9~-~15}{4}=-1,5~~\rightarrow~nao~convem$


x = 6 cm