Question

The square of (2$x$ -1) is equal to 5. If one of the values of $x$ is $\frac{1-\sqrt{5}}{2}$, what is the value of $x$ ?

• A. x= (1 + √5)/2
• B. x = (-1 - √5)/2
• C. x = (-1 + √5)/2
• D. x= (1 + √6)/2

Answer 1

The correct option is A

x= (1 + √5)/2

$(2x-1{)}^2$ = 5

$(2x-1)=\pm \sqrt{5}$

$2x=\pm \sqrt{5}+1$

$x=(1\pm \sqrt{5})2$

$x$ = $\frac{1+\sqrt{5}}{2}$ or $x$= $\frac{1-\sqrt{5}}{2}$