Question

resolva as equações do 2°grau incompletas em |R

a)
$x {}^{2} - 36 = 0$
b)
$2 x {}^{2} - 50 = 0$
c)
$3x { }^{2} - 147 = 0$
d)
$- 5 + 5x {}^{2} = 0$
e)
$x {}^{2} - \frac{25}{9} = 0$
f)
$3x {}^{2} = 81$

Answer 1

$a) \\ x^{2} -36=0 \\ x^{2} =36 \\ x=\pm \sqrt{36} \\ x=\pm6 \\ \\ b) \\ 2x^2-50=0 \\ 2x^2=50 \\ x^2=50\div2 \\ x^{2} =25 \\ x=\pm \sqrt{25} \\ x=\pm5 \\ \\ c) \\ 3x^2-147=0 \\ 3 x^{2} =147 \\ x^{2} =147\div3 \\ x^{2} =49 \\ x=\pm \sqrt{49} \\ x=\pm7$

$d) \\ -5+5x^2=0 \\ 5x^2=5 \\ x^{2} =5\div5 \\ x^{2} =1 \\ x=\pm \sqrt{1} \\ x=\pm1 \\ \\ e) \\ x^{2} - \frac{25}{9} =0 \\ \\ x^{2} = \frac{25}{9} \\ \\ x=\pm \sqrt{ \frac{25}{9} } \\ \\ x=\pm \frac{5}{3} \\ \\ f) \\ 3x^2-81=0 \\ 3x^2=81 \\ x^{2} =81\div3 \\ x^{2} =9 \\ x=\pm \sqrt{9} \\ x=\pm3$