Question

Product of (6+i)(2+9i)

Answer 1

`(6+i)(2+9i)=18+54i+2i-9=9+56i`

Answer 2

(6 + i)(2 + 9i) = 3 + 56i

Explanation:

Use FOIL: (a + b)(c + d) = ac + ad + bc + bd

and i² = -1

(6 + i)(2 + 9i) = (6)(2) + (6)(9i) + (i)(2) + (i)(9i)

= 12 + 54i + 2i + 9i²

= 12 + 54i + 2i + 9(-1)

= 12 + 54i + 2i - 9 combine like terms

= (12 - 9) + (54i + 2i)

= 3 + 56i