Question

What is the solution of √x-5 = x-11

Answer 1

Hey!


To solve x in this equation we must first add five to both sides to get $\sqrt{x}$ on its own.

Original Equation :
$\sqrt{x} - 5 = x - 11$

New Equation {Added 5 to Both Sides} :
$\sqrt{x} =x-6$

Now we must square both sides of the equation.

Old Equation :
$\sqrt{x} =x-6$

New Equation {Changed by Squaring Both Sides} :
$x= x^{2} -12x+36$

And now we must solve the new equation.

Step 1 - Switch sides
$x^{2} -12x+36=x$

Step 2 - Subtract x from both sides
$x^{2} -12x+36-x=x-x$

Step 3 - Simplify
$x^{2} -13x+36=0$

Now we need to solve the rest of the equation using the quadratic formula.

$\frac{-(-13)+ \sqrt{(-13) ^{2}-4*1*36 } }{2*1}$

${13+ \sqrt{(-13)^{2}-4*1*36 }=13+ \sqrt{25}$

$\frac{13+ \sqrt{25}}{2}$

$\sqrt{25}=5$

$\frac{13+5}{2}$

$\frac{18}{2}$

9

$\frac{-(-13)- \sqrt{(-13) ^{2} -4*1*36} }{2*1}$

4

So, this means that in the equation $\sqrt{x} -5=x-11$,  x = 9  and  x = 4.

Hope this helps!


- Lindsey Frazier ♥