Question

calcule:

b)X²=7x-12

c)-20=-x-x²

d)--9x²=5 -6x

ME AJUDEM!!​

Answer 1

$b) \\ x {}^{2} = 7x - 12 \\ x {}^{2} - 7x + 12 = 0 \\ \boxed{a = 1 \: ,\: b = - 7 \:, \: c = 12} \\ x = \frac{ - b ±\sqrt{b {}^{2} - 4ac} }{2a} \\ x = \frac{ - ( - 7)± \sqrt{( - 7) {}^{2} - 4 \: . \: 1 \: . \: 12} }{2 \: . \: 1} \\ x = \frac{7 ±\sqrt{49 - 48} }{2} \\ x = \frac{7 ± \sqrt{1} }{2} \\ x = \frac{7 ±1}{2} \\ x = \frac{7 + 1}{2} = \frac{8}{2} = \boxed{\boxed{\boxed{4}}} \\ x = \frac{7 - 1}{2} = \frac{6}{2} = \boxed{\boxed{\boxed{3}}}$

$c) \\ - 20 = - x - x {}^{2} \\ x {}^{2} + x - 20 = 0 \\ \boxed{a = 1 \: ,\: b = 1 \: ,\: c = - 20} \\ x = \frac{ - b ±\sqrt{b {}^{2} - 4ac} }{2a} \\ x = \frac{ - 1 ± \sqrt{1 {}^{2} - 4 \: . \: 1 \: . \: ( - 20) } }{2 \: . \: 1} \\ x = \frac{ - 1 ± \sqrt{1 + 80} }{2} \\ x = \frac{ - 1± \sqrt{81} }{2} \\ x = \frac{ - 1 ±9}{2} \\ x = \frac{ - 1 + 9}{2} = \frac{8}{2} = \boxed{\boxed{\boxed{4}}} \\ x = \frac{ - 1 - 9}{2} = \frac{ - 10}{2} = \boxed{\boxed{\boxed{ - 5}}}$

$d) \\ - 9x {}^{2} = 5 - 6x \\ - 9x {}^{2} + 6x - 5 = 0 \\ \boxed{a = - 9 \:, \: b = 6 \: , \: c = - 5} \\ x = \frac{ - b ± \sqrt{b {}^{2} - 4ac } }{2a} \\ x = \frac{ - 6± \sqrt{6 {}^{2} - 4 \: . \: ( - 9) \: . \: ( - 5) } }{2 \: . \: ( - 9)} \\ x = - \frac{ - 6± \sqrt{36 - 180} }{18} \\ x = - \frac{ - 6 ±\sqrt{ - 144} }{18} \\ \boxed{\boxed{\boxed{x∉ℝ}}}$

atte. yrz