Answer
$(2+5i)(2-5i) = 29$
Work Step by Step
1. $(2+5i)(2-5i)$
2. Use the difference of two squares formula $a^{2}-b^{2} = (a+b)(a-b)$ (or Multiply the two binomials together (use the FOIL method to distribute the First, Outer, Inner, and Last terms)):$4-25i^{2}$
3. Change $-25i^{2}$ to 25, because $i^{2} = -1$ and $-25\times-1 = 25$:$4+25$
4. Add the two numbers together:$29$
