Given the equation [tex]$x-4 \sqrt{x}+4=0$[/tex]

(i) If [tex]$u=\sqrt{x}$[/tex] and [tex][tex]$u^2=x$[/tex][/tex], form a quadratic equation in [tex]$u$[/tex] and show that [tex]$u=2$[/tex].



Answer :

Sure! Let’s solve the given equation step by step.

We start with the given equation:
[tex]\[ x - 4\sqrt{x} + 4 = 0 \][/tex]

(i) Let [tex]\( u = \sqrt{x} \)[/tex]. Then [tex]\( u^2 = x \)[/tex].

Substitute [tex]\( u \)[/tex] and [tex]\( u^2 \)[/tex] into the original equation:
[tex]\[ u^2 - 4u + 4 = 0 \][/tex]

Now, we need to solve this quadratic equation for [tex]\( u \)[/tex].

To solve the quadratic equation [tex]\( u^2 - 4u + 4 = 0 \)[/tex], we can use factoring.

Notice that the quadratic [tex]\( u^2 - 4u + 4 \)[/tex] can be written as:
[tex]\[ (u - 2)(u - 2) = 0 \][/tex]
or
[tex]\[ (u - 2)^2 = 0 \][/tex]

For the product to be zero, one of the factors must be zero:
[tex]\[ u - 2 = 0 \][/tex]

So,
[tex]\[ u = 2 \][/tex]

Therefore, the value of [tex]\( u \)[/tex] that satisfies the given equation is:
[tex]\[ u = 2 \][/tex]

Thus, we have shown that [tex]\( u = 2 \)[/tex].