Question

Using the quadratic formula to solve x2 35-x, what are the values of x?

-12-121
-12-11
54.
12/19
51 21
2

Answer 1

x = (-1 ± √21) / 2

The first choice

Explanation:

x² = 5 - x

Put in standard form

x² + x - 5 = 0

Use quadratic equation

x = ( -b ± √( b² - 4ac) ) / (2a)

Plug in a = 1, b = 1 , c = -5

x = (-1 ± √( 1² - 4*1*(-5)) ) / 2

evaluate

x = (-1 ± √21) / 2