Final answer:
To write the expression zz in standard form a + bi, we substitute the value of z into the expression. By using the FOIL method, we can expand the expression and simplify it to obtain the standard form -20 - 48i.
Step-by-step explanation:
To write the expression zz in standard form a + bi, we substitute the value of z into the expression. In this case, z = 4 - 6i. So, the expression becomes (4 - 6i)(4 - 6i).
We can expand this expression using the FOIL method:
(4 - 6i)(4 - 6i) = 16 - 24i - 24i + 36i²
Next, we can simplify the expression by combining like terms:
16 - 24i - 24i + 36i² = 16 - 48i + 36i²
The imaginary unit i is defined as i² = -1. So, i² = -1. Substituting this value into the expression, we get:
16 - 48i + 36(-1) = 16 - 48i - 36 = -20 - 48i
Therefore, the expression zz in standard form a + bi is -20 - 48i.