How do you simplify # (-3 + i)(2 + 7i) # and write in a+bi form?
1 Answer
Dec 22, 2015
Use FOIL then combine terms to find:
#(-3+i)(2+7i)=-13-19i#
Explanation:
You can use FOIL to multiply the two binomials then combine terms:
#(-3+i)(2+7i)#
#= stackrel "First" overbrace((-3)(2)) + stackrel "Outside" overbrace((-3)(7i)) + stackrel "Inside" overbrace((i)(2)) + stackrel "Last" overbrace((i)(7i))#
#=-6-21i+2i+7i^2#
#=-6-19i-7#
#=-13-19i#
