Chapter Thirteen — Radical Expressions and Equations
The Humongous Book of Algebra Problems
291
Note: Problems 13.40–13.42 refer to complex numbers a = 2 – 3i and b = –4 + 5i.
13.40 Calculate a + b, the sum of the complex numbers, and a – b, the difference of
the complex numbers.
Adding and subtracting complex numbers is very similar to adding and
subtracting polynomials—combine like terms.
To calculate a – b, multiply b by –1.
Note: Problems 13.40–13.42 refer to complex numbers a = 2 – 3i and b = –4 + 5i.
13.41 Calculate a · b.
Multiply complex numbers the same way you would multiply two binomials.
According to Problem 13.39, . Substitute that value into the expression.
If you’re not
sure how to multiply
binomials, look at
Problem 11.19.