Question

4 - Resolva agora você:
a) x² - 49 = 0
b) x² = 1
c) 2x² - 50 = 0
d) 7x² - 7 = 0
e) 5x² - 15 = 0
f) 21 = 7x²
g) 5x² + 20 = 0
h) 7x² + 2 = 30
i) 2x² - 90 = 8
j) 4x² - 27 = x²
k) 8x² = 60 – 7x²

Answer 1

Resposta:

Explicação passo-a-passo:

$A) \\x^{2} -49=0\\\\x^{2} =49\\x = +-\sqrt{49} \\x = +-7\\\\B) \\x^{2} = 1\\\\x = +-\sqrt{1} \\\\x = +-1\\\\C) \\2x^{2} -50=0\\2x^{2} =50\\x^{2} = \frac{50}{2} \\x^{2} =25\\x=+-\sqrt{25} \\x = +-5\\\\D)\\7x^{2} -7=0\\7x^{2} = 7\\x^{2} =\frac{7}{7} \\x^{2} = 1\\x=+-\sqrt{1} x = +-1\\\\E) \\5x^{2} -15=0\\5x^{2} =15\\x^{2} =\frac{15}{5}\\x^{2} =3\\x= +-\sqrt{3} \\\\F)\\21 = 7x^{2} \\7x^{2} =21\\x^{2} =\frac{21}{7} \\x^{2} =3\\x=+-\sqrt{3}$

$G)\\5x^{2} +20=0\\5x^{2} = -20\\x^{2} =\frac{-20}{5} \\x^{2} =-4\\x=+-\sqrt{-4}$

x não existe

$H)\\7x^{2} +2=30\\7x^{2} =30-2\\7x^{2} =28\\x^{2} =\frac{28}{7} \\x^{2} =4\\x =+-\sqrt{4} \\x = +-2\\\\I)\\2x^{2} -90=8\\2x^{2} =8+90\\2x^{2} =98\\x^{2} = \frac{98}{2} \\x^{2} =49\\x=+-\sqrt{49}\\x=+-7\\\\J)\\4x^{2} -27=x^{2} \\4x^{2} -x^{2} =27\\3x^{2} =27\\x^{2} =\frac{27}{3} \\x^{2} =9\\x = +-\sqrt{9} \\x = +-3\\\\K) \\8x^{2} =60-7x^{2} \\8x^{2} +7x^{2} =60\\15x^{2} =60\\x^{2} =\frac{60}{15}\\x^{2} =4\\x=+-\sqrt{4} \\x= +-2$