Question

Solve. 3x2 + 4x = –5 using quadratic equation ...?

Answer 1

3x^2 + 4x - 5 = 0 
x = [-b ±√(b^2 - 4ac)]/2a 

a = 3 
b = 4 
c = -5 

x = [-4 ±√(16 + 60)]/6 
x = [-4 ±√76]/6 
x = [-4 ±√(2^2 * 19)]/6 
x = [-4 ±2√19]/6 
x = [-2 ±√19]/3 

x = [-2 + √19]/3 
x = [-2 + 4.35]/3 
x = 2.35/3 
x = 0.78 (rounded to the nearest hundredth) 

x = [-2 - ±√19]/3 
x = [-2 - 4.35]/3 
x = -6.35/3 
x = -2.12 (rounded to the nearest hundredth) 

∴ x = -2.12 , 0.78 (rounded to the nearest hundredth)