Question

7. Resolva as equações:

a) -25+ 100x²=0

b) x²-81÷4=o

Answer 1

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a)

$-25+100x^2=0 \\ 100x^2=25 \\ x^2= \frac{25}{100}} ~~simplificando~~ x^2= \frac{1}{4} \\ \\ x=\pm \sqrt{ \frac{1}{4} } \\ \\ x=\pm \frac{1}{2} \\ \\ \\ b) \\ x^2- \frac{81}{4} =0 \\ \\ x^2= \frac{81}{4} \\ \\ x=\pm \sqrt{ \frac{81}{4} } \\ \\ x=\pm \frac{9}{2}$