Question

equacao do segundo grau ×2+4×-21=0

Answer 1

A = 1
B = 4
C = - 21

∆ = b² - 4.a.c
∆ = 4² - 4.1. (-21)
∆ = 16 - (-84)
∆ = 16 + 84
∆ = 100

x = - b +- √∆
--------------
2.a

x = - 4 +- √100
---------------
2.1

x = - 4 +- 10
----------------
2

x1 = - 4 + 10
--------------- = 6/2 = 3
2

x2 = - 4 - 10
-------------- = - 14/2 = - 7
2

S = {3, -7}

Answer 2

Olá.

• x² + 4x - 21 = 0

A = 1
B = 4
C = -21

Δ = b² - 4ac
Δ = 16 - 4(1)(-21)
Δ = 16 + 84
Δ = 100

x = -b +- √Δ / 2a
x = -4 +- 10 / 2

x1 = -4 - 10 / 2 = -7
x2 = -4 + 10 / 2 = 3

S = {-7, 3}

Bons estudos.