How do you solve x^2 + 5x - 1 = 0x2+5x−1=0?

1 Answer
Roella W.
Jun 26, 2015

Use the standard formula x = (-b +- sqrt(b^2 - 4ac))/(2a)x=−b±√b2−4ac2a to solve an expression ax^2 + bx + c = 0ax2+bx+c=0

Explanation:

In this case x =( -5 +- sqrt(5^2 -4*1*(-1)))/(2*1)x=−5±√52−4⋅1⋅(−1)2⋅1
x =( -5 +- sqrt(25 +4))/2x=−5±√25+42
x = (-5 +- sqrt(29))/2x=−5±√292
x=(-5+sqrt(29))/2 or (-5-sqrt(29))/2x=−5+√292or−5−√292
Using a calculator gives
x=-5+5.385x=−5+5.385 or x=-5-5.385x=−5−5.385
x=0.385x=0.385 or x=-10.385x=−10.385

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