How do you solve 5x ^ { 2} + 5x - 1= 0?

1 Answer
Mar 12, 2017

x=0.171 or x=-1.171

Explanation:

5x^2+5x-1=0

Standard form of a quadratic equation:

ax^2+bx+c=0

x=(-b+sqrt(b^2-4ac))/(2a)

:.x=((-5)+-sqrt(5^2-(4*5*-1)))/(2*5)

:.x=(-5+-sqrt(25+20))/10

:.x=(-5+sqrt45)/10 or x=(-5-sqrt45)/10

:.x=(-5+6.708203933)/10 or x=(-5-6.708203933)/10

:.x=1.708203933/10 or x=-11.708203933/10

:.x=0.1708203933 or x=-1.1708203933

:.x=0.171 or x=-1.171