Question

Which shows the correct substitution of the values a, b, and c from the equation –2 = –x + x² – 4 into the quadratic formula?

Answer 1

-2 = - x + x^2 -4 => x^2 - x - 4 + 2 = 0

x^2 - x - 2 = 0

a is the coefficient of x^2 => a = 1

b is the coefficient of x => b = - 1

c is the constant term => c = - 2

quadratic equation: [- b +/- √(b^2 - 4ac) ] / 2a =

= { 1 +/- √[ (-1)^2 - 4(1)(-2)] } / (2(1) = { 1 +/- √ (1 + 8) } / 2 = {1 +/- √9} / 2 =

= { 1 +/- 3} / 2