SOLUTION: . Simplify the following product of complex numbers. (-1 + 3i) • (-9 – 7i) can someone explain this to me

Algebra ->  Problems-with-consecutive-odd-even-integers -> SOLUTION: . Simplify the following product of complex numbers. (-1 + 3i) • (-9 – 7i) can someone explain this to me      Log On


   

Question 502372: . Simplify the following product of complex numbers.
(-1 + 3i) • (-9 – 7i)
can someone explain this to me
Answer by geetha_rama(94) About Me  (Show Source):
You can put this solution on YOUR website!
(-1+3i) * (-9 - 7i)
= -1*-9 + 3i*(-9) -1*(-7i) + (3i)*(-7i)
= 9 -27i + 7i -21i^2
= 9 -20i + 21 (since i^2 = -1)
= 30 -20i
= 10* (3 -2i)