Question

multiply (-10 + 5i) (-10 - 5i). (1 point)

Explanation:

Step1: Use the FOIL method

\[(- 10 + 5i)(-10 - 5i)=(-10)\times(-10)+(-10)\times(-5i)+5i\times(-10)+5i\times(-5i)\]

Step2: Simplify each term

\[(-10)\times(-10) = 100\]
\[(-10)\times(-5i)=50i\]
\[5i\times(-10)=-50i\]
\[5i\times(-5i)=-25i^{2}\]
Since \(i^{2}=-1\), then \(-25i^{2}=-25\times(-1) = 25\)

Step3: Combine like - terms

\[100 + 50i-50i+25=100 + 25+(50i-50i)=125\]

Answer:

125