$\"\"$

The given values $\"\"$ .

Where $\"\"$ is first term and r is common ratio.

Apply alternative formula for sum of a geometric series $\"\"$ .

$\"\"$ (Substitute $\"\"$ ) $\"\"$

$\"\"$ (Subtract denominator: $\"\"$ )

$\"\"$ (Multiply: $\"\"$ )

$\"\"$ (Subtract: $\"\"$ )

$\"\"$ (Divide: $\"\"$ ) $\"\"$

The value of $\"\"$ .