Question

Calcule o valor de a, b, c e logo após calcule o discriminate
a)2x² - 7x = 15
b) 4x² + 9 = 12x
c)x² = x + 12
d) 2x² = -12x - 18
e) x² + 9 = 4x
f) 25x² = 20x – 4
g) 2x = 15 – x²
h) x² + 3x – 6 = -8
i) x² + x – 7 = 5
j) 4x² - x + 1 = x + 3x²
k) x² + 5x + 6 = 0
l) x² - 7x + 12 = 0
m) x² + 5x + 4 = 0
n) 7x² + x + 2 = 0
o) x² - 18x + 45 = 0
p)4x² - 27 = x²
q) 8x² = 60 – 7x²
r) 3(x² - 1 ) = 24
s) 2(x² - 1) = x² + 7

Answer 1

Resposta:

a)

a = 2; b = - 7; c = - 15

x1 = 20/4 = 5

x2 = - 6/4 = - 3/2

Explicação passo-a-passo:

a)2x² - 7x = 15

2x² - 7x - 15 = 0

a = 2; b = - 7; c = - 15

x = (7 ± √(7² + 4.2.15))/2.2

x = (7 ± √(49 + 120))/4

x = (7 ± √169)/4

x = (7 ± 13)/4

x1 = 20/4 = 5

x2 = - 6/4 = - 3/2