=(4-5i)(4+5i)

Solution for =(4-5i)(4+5i) equation:

Simplifying
0 = (4 + -5i)(4 + 5i)

Multiply (4 + -5i) * (4 + 5i)
0 = (4(4 + 5i) + -5i * (4 + 5i))
0 = ((4 * 4 + 5i * 4) + -5i * (4 + 5i))
0 = ((16 + 20i) + -5i * (4 + 5i))
0 = (16 + 20i + (4 * -5i + 5i * -5i))
0 = (16 + 20i + (-20i + -25i2))

Combine like terms: 20i + -20i = 0
0 = (16 + 0 + -25i2)
0 = (16 + -25i2)

Solving
0 = 16 + -25i2

Solving for variable 'i'.

Move all terms containing i to the left, all other terms to the right.

Add '25i2' to each side of the equation.
0 + 25i2 = 16 + -25i2 + 25i2
Remove the zero:
25i2 = 16 + -25i2 + 25i2

Combine like terms: -25i2 + 25i2 = 0
25i2 = 16 + 0
25i2 = 16

Divide each side by '25'.
i2 = 0.64

Simplifying
i2 = 0.64

Take the square root of each side:
i = {-0.8, 0.8}