Question

Como resolvo essas equações de 2° grau:
2x² - 90 = 0
4x² - 27 = 0
7x² + 2 = 30
x² - 5x = 0

Answer 1

2 (x)2 - 90 = 0
x 2 = 90 / 2
x 2 = 45
x = √45
x = 3 √5
4(x) 2 - 27 = 0
4 (x ) 2 = 27
x 2 = 27 / 4
x = √27 ÷ √4

x = 3√3 / 2

7 (x ) 2 + 2 = 30
7 (x ) 2 = 30 - 2
7( x ) 2 = 28
x 2 = 28:/ 7
x 2 = 4
x = √4
x = 2

x 2 - 5x = 0
x ( x - 5 ) = 0
x = 0
x - 5 = 0
x = 5