Question

Pls i need this today help me

Answer 1

Answer:

Step-by-step explanation:

a) 4x² + 20 = 0

          4x² = -20

            x² = -20/4

            x² = -5 = i² *5

             x = √i²5

            x = i√5

b) 4x² + 5 = -7

        4x² = -7 - 5

       4x² = - 12

          x² = -12/4

         x² = -3 = 3i²

        x = i√3

c) x² + 4x + 20 = 0

a = 1 ; b =4  ; c =20

$x = \frac{-b+\sqrt{b^{2}-4ac}}{2a} and \frac{-b-\sqrt{b^{2}-4ac}}{2a};\\\\x = \frac{-4+\sqrt{16-4*1*20}}{2*1} and\frac{-4-\sqrt{16-4*1*20}}{2*1}\\\\=\frac{-4+\sqrt{16-80}}{2} and \frac{-4-\sqrt{16+80}}{2}\\\\=\frac{-4+\sqrt{-64}}{2} and \frac{-4-\sqrt{64}}{2}\\\\= \frac{-4+8i}{2} and\frac{-4-8}{2}$

  = (-2 +4i)  & -12/2

  = (-2 + 4i) and (-6)