We are asked to evaluate the expression $(2 + \sqrt{-4})(-1 + \sqrt{-9})$.

AlgebraComplex NumbersImaginary NumbersArithmetic Operations
2025/3/7

1. Problem Description

We are asked to evaluate the expression (2+4)(1+9)(2 + \sqrt{-4})(-1 + \sqrt{-9}).

2. Solution Steps

First, we simplify the square roots of negative numbers by using the imaginary unit ii, where i=1i = \sqrt{-1}.
4=41=41=2i\sqrt{-4} = \sqrt{4 \cdot -1} = \sqrt{4} \cdot \sqrt{-1} = 2i
9=91=91=3i\sqrt{-9} = \sqrt{9 \cdot -1} = \sqrt{9} \cdot \sqrt{-1} = 3i
Now substitute these values into the expression:
(2+2i)(1+3i)(2 + 2i)(-1 + 3i)
Expand the product using the distributive property (FOIL):
(2+2i)(1+3i)=2(1)+2(3i)+2i(1)+2i(3i)=2+6i2i+6i2(2 + 2i)(-1 + 3i) = 2(-1) + 2(3i) + 2i(-1) + 2i(3i) = -2 + 6i - 2i + 6i^2
Recall that i2=1i^2 = -1. Substitute this value:
2+6i2i+6(1)=2+4i6=8+4i-2 + 6i - 2i + 6(-1) = -2 + 4i - 6 = -8 + 4i

3. Final Answer

8+4i-8+4i