How to find a rational number from an exponent - PSAT Math
Card 0 of 49
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From the equation in the problem statement

Now squaring both sides we get
this is a quadratic equation which equals

and the factors of this equation are

This gives us
.
However, if we plug these solutions back into the original equation,
does not create an equality. Therefore,
is an extraneous solution.
From the equation in the problem statement
Now squaring both sides we get
this is a quadratic equation which equals
and the factors of this equation are
This gives us .
However, if we plug these solutions back into the original equation, does not create an equality. Therefore,
is an extraneous solution.
Rationalize the denominator:

Rationalize the denominator:
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The conjugate of
is
.
Now multiply both the numerator and the denominator by 
and you get:


Hence we get

The conjugate of is
.
Now multiply both the numerator and the denominator by
and you get:
Hence we get
Solve for
:

Solve for :
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Solve for
.

Solve for .
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If,

What does 
If,
What does
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If
,
then
.
If ,
then .
For some positive integer
, if
, what is the value of
?
For some positive integer , if
, what is the value of
?
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If
, then
must equal 3 (Note that
cannot be -3 because you need it to be positive.
Now, plug
into the new equation
:



If , then
must equal 3 (Note that
cannot be -3 because you need it to be positive.
Now, plug into the new equation
:
Tap to see back →
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From the equation in the problem statement

Now squaring both sides we get
this is a quadratic equation which equals

and the factors of this equation are

This gives us
.
However, if we plug these solutions back into the original equation,
does not create an equality. Therefore,
is an extraneous solution.
From the equation in the problem statement
Now squaring both sides we get
this is a quadratic equation which equals
and the factors of this equation are
This gives us .
However, if we plug these solutions back into the original equation, does not create an equality. Therefore,
is an extraneous solution.
Rationalize the denominator:

Rationalize the denominator:
Tap to see back →
The conjugate of
is
.
Now multiply both the numerator and the denominator by 
and you get:


Hence we get

The conjugate of is
.
Now multiply both the numerator and the denominator by
and you get:
Hence we get
Solve for
:

Solve for :
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Solve for
.

Solve for .
Tap to see back →
If,

What does 
If,
What does
Tap to see back →
If
,
then
.
If ,
then .
For some positive integer
, if
, what is the value of
?
For some positive integer , if
, what is the value of
?
Tap to see back →
If
, then
must equal 3 (Note that
cannot be -3 because you need it to be positive.
Now, plug
into the new equation
:



If , then
must equal 3 (Note that
cannot be -3 because you need it to be positive.
Now, plug into the new equation
:
Tap to see back →
Tap to see back →
From the equation in the problem statement

Now squaring both sides we get
this is a quadratic equation which equals

and the factors of this equation are

This gives us
.
However, if we plug these solutions back into the original equation,
does not create an equality. Therefore,
is an extraneous solution.
From the equation in the problem statement
Now squaring both sides we get
this is a quadratic equation which equals
and the factors of this equation are
This gives us .
However, if we plug these solutions back into the original equation, does not create an equality. Therefore,
is an extraneous solution.
Rationalize the denominator:

Rationalize the denominator:
Tap to see back →
The conjugate of
is
.
Now multiply both the numerator and the denominator by 
and you get:


Hence we get

The conjugate of is
.
Now multiply both the numerator and the denominator by
and you get:
Hence we get
Solve for
:

Solve for :
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Solve for
.

Solve for .
Tap to see back →
If,

What does 
If,
What does
Tap to see back →
If
,
then
.
If ,
then .