any help appriciated simplify and express the following in the form a+bi?

3 ⤊

any help appriciated simplify and express the following in the form a+bi?

(5+12i)/(8+9i)

2007-11-20 05:45:45 · 2 answers · asked by evosteo 2 in Science & Mathematics ➔ Mathematics

2 answers

(5+12i)/(8+9i)

Multiply the top and bottom by the conjugate of 8+9i.

(5+12i)(8-9i) / [(8+9i)(8-9i)]

Use FOIL to multiply it out.
= (40 - 45i + 96i - 108i^2) / (64 - 72i + 72i - 81i^2)
= (40 + 51i + 108) / (64 + 81)
= (148 + 51i) / 145
= (148/145) + (51/145)i

2007-11-20 11:43:51 · answer #1 · answered by MsMath 7 · 0⤊ 2⤋

(5 + 12i) (8 - 9i) / (64 + 81)
(40 + 51 i + 108) / (145)
(148 + 51 i) / (145)

2007-11-20 21:33:00 · answer #2 · answered by Como 7 · 3⤊ 1⤋