Question

1-calcule as raízes das equações do 2° grau incompletas:
a) x²-25=0 b)2x²-18=0 c)7x²-14=0 d)x²-9x=0 e)x²-5x=0 f)x²-64=0 g)x²-16=0​

Answer 1

Resposta e explicação passo-a-passo:

$a) x^2 - 25 = 0\\x^2 = 25\\x = \sqrt{25}\\x = 5, -5\\\\b) 2 x^2 -18 = 0\\2x^2 = 18\\x^2 = 18 :2\\x^2 = 9\\x = \sqrt{9}\\x = 3, -3 \\\\c) 7x^2 - 14 = 0\\7x^2 = 14\\x^2 = 14:7\\x^2 = 2\\x = \sqrt{2}, -\sqrt{2} \\\\d)x^2 - 9x = 0\\x (x-9) = 0\\x = 0, 9\\\\e) x^2 - 5x = 0\\x (x-5) = 0\\x= 0, 5\\\\f) x^2 - 64 = 0\\x^2 = 64\\x = \sqrt{64} \\x = 8, -8\\\\g)x^2 - 16 = 0\\x^2 = 16\\x = \sqrt{16}\\x = 4, -4$

Espero ter ajudado :)