What is the solution of the equation x2 – x – 1 + 0?
-
A.
x = 1.6 and x = -0.6 -
B.
x = -1.6 and x = 0.6 -
C.
x = 1.6 and x = 0.6 -
D.
x = -1.6 and x = -0.6
Correct Answer: Option A
Explanation
(x^{2} – x – 1 = 0)
Using the quadratic formula,
(x = frac{-b pm sqrt{b^{2} – 4ac}}{2a})
a = 1, b = -1, c = -1.
(x = frac{-(-1) pm sqrt{(-1)^{2} – 4(1)(-1)}}{2(1)})
(x = frac{1 pm sqrt{1 + 4}}{2} = frac{1 pm sqrt{5}}{2})
(x = frac{1 + 2.24}{2} ; x = frac{1 – 2.24}{2})
(x = frac{3.24}{2}; x = frac{-1.24}{2})
(x = 1.62 ; x = -0.61 )
(x approxeq 1.6; -0.6)