Question

me ajudem estou no começo do 9 ano e o professor me passouu isso de tarefa, para achar o a,b,c me ajudeeem  a)x²-6x+8=0 b)x²-10x+21=0 c)x²-4x+3

 

 

Answer 1

$x^2-6x+8 = 0\\\\\ \Delta = b^2-4(a)(c)\\\\\ \Delta = (-6)^2-4(1)(8)\\\\\ \Delta = 36-32\\\\\ \Delta = 4$

$x = \frac{-b+\ ou\ -\sqrt{\Delta}}{2a}$

$x = \frac{6+\ ou\ -2}{2}\\\\\ x^i = \frac{6+2}{2} = \frac{8}{2} = 4\\\\ x^i^i = \frac{6-2}{2} = \frac{4}{2} = 2\\\\ \boxed{S(2,4)}$

$x^2-10x+21=0\\\\ \Delta = (-10)^2-4(1)(21)\\\\ \Delta = 100-84\\\\ \Delta = 16$

$x = \frac{-b+\ ou\ -\sqrt{\Delta}}{2a}\\\\\ x = \frac{10+\ ou\ -4}{2}\\\\\ x^i = \frac{10+4}{2} = \frac{14}{2} = 7\\\\ x^i^i = \frac{10-4}{2} = \frac{6}{2} = 3\\\\ \boxed{S(3,7)}$

$x^2-4x+3=0\\\\\ \Delta = 16-12\\\\ \Delta = 4$

$x = \frac{4+\ ou\ -2}{2}\\\\\ x^i = \frac{4+2}{2} = \frac{6}{2} = 3\\\\ x^i^i = \frac{4-2}{2} = \frac{2}{2} = 1\\\\ \boxed{S(1,3)}$

Answer 2

ax² + bx + c = 0                         
a) x² - 6x + 8 = 0                a = 1      b = -6       c = 8
b) x² - 10x + 21 = 0             a = 1      b = -10     c = 21
c) x² - 4x + 3 = 0                a = 1       b = -4      c = 3