Answer:
A) X = -5 , X = 8
B) X = 4/5 , X = -2
Explanation:
A. X² - 3X - 40 = 0
Nosotros factorizamos
X² - 8X + 5X - 40 = 0
(X² - 8X) + (5X - 40) = 0
X(X - 8) + 5(X - 8) = 0
(X + 5) (X - 8) = 0
X + 5 = 0
X = -5
X - 8 = 0
X = 8
X = -5 , X = 8
B. 5X² + 6X - 8 = 0
Nosotros factorizamos
5X² + 10X - 4X - 8 = 0
(5X² + 10X) - (4X - 8) = 0
5X(X + 2) -4(X + 2) = 0
(5X - 4) (X + 2) = 0
5X - 4 = 0
5X = 4
X = 4/5
X + 2 = 0
X = -2
X = 4/5 , X = -2