Question

How do you simplify (2+7i)(2−7i) and write in a+bi form?

Answer 1

Given , (2+7i)(2-7i)

${2}^{2} - {(7i)}^{2} \\ \\ = 4 - 49 {i}^{2} \\ \\ = 4 - 49( - 1) \\ \\ = 4 + 49 \\ \\ = 53 \\ = 53 + 0 \times i$

is the a+ib form