Question

ME AJUDEM PFV É PRA AMANHÃ

Answer 1

$a) x^{2} +4x-5=0\\\\a = 1\\b = 4\\c = -5\\Delta = b^{2} -4*a*c\\Delta = 4^{2}-4*1*(-5)\\Delta = 16 -(- 20)\\Delta = 16 + 20\\Delta = 36\\\\X1 = \frac{-b+\sqrt[]{Delta}}{2*a} \\X1 = \frac{-4+\sqrt[]{36}}{2*1}\\X1 = -2+6\\X1=4 \\\\X2 = \frac{-b-\sqrt[]{Delta}}{2*a} \\X2 = \frac{-4-\sqrt[]{36}}{2*1} \\X2 = -2 - 6\\X2 = -8$

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$b) 4x^{2} +2x-6=0\\\\a = 4\\b = 2\\c = -6\\Delta = b^{2} -4*a*c\\Delta = 2^{2}-4*4*(-6)\\Delta = 4 -(- 96)\\Delta = 4 + 96\\Delta = 100\\\\X1 = \frac{-b+\sqrt[]{Delta}}{2*a}\\X1 = \frac{-4+\sqrt[]{100}}{2*1}\\X1 = -4+10\\X1=6\\\\X2 = \frac{-b-\sqrt[]{Delta}}{2*a}\\X2 = \frac{-4-\sqrt[]{100}}{2*1}\\X2 = -4 - 10\\X2 = -14$

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$c) x^{2}-9=0\\a = 1\\b = 0\\c = -9\\Delta = b^{2}-4*a*c\\Delta = 0^{2}-4*1*-9\\Delta = -4*(-9)\\Delta = 36\\\\X1 = \frac{ -b + \sqrt{Delta}}{2*a}\\X1 = \frac{0+\sqrt{36}}{2*1}\\X1 = \frac{6}{2}\\X1 = 3\\\\X2 = \frac{ -b - \sqrt{Delta}}{2*a}\\X2 = \frac{0-\sqrt{36}}{2*1}\\X2 = \frac{-6}{2}\\X2 = -3$