$\"\"$

The standard form of the complex number is $\"\"$ , where a and b are real numbers.

The expression is " $\"\"$ ".

$\"\"$ (Multiply numerator and denominator by 1 + 2i)

$\"\"$

$\"\"$ (Apply the formula $\"\"$ ) $\"\"$

$\"\"$ (Apply Foil Method)

$\"\"$ (The imaginary unit $\"\"$ )

$\"\"$

$\"\"$ (Take out common term 5 in numerator)

$\"\"$ .

$\"\"$

The standard form is 4 + i.