Questions: What is the standard form of (7-5 i)(2+3 i) ?
A. -11+29 i
B. -29+11 i
C. 29+11 i
D. 11-29 i
Transcript text: What is the standard form of $(7-5 i)(2+3 i)$ ?
A. $-11+29 i$
B. $-29+11 \mathrm{i}$
C. $29+11 \mathrm{i}$
D. $11-29 \mathrm{i}$
Solution
Solution Steps
To find the standard form of the product of two complex numbers, we use the distributive property to expand the expression \((7-5i)(2+3i)\). This involves multiplying each term in the first complex number by each term in the second complex number. After expanding, we combine like terms and simplify, remembering that \(i^2 = -1\).
Step 1: Expand the Expression
To find the product of the complex numbers \((7-5i)\) and \((2+3i)\), we use the distributive property:
\[
(7-5i)(2+3i) = 7 \cdot 2 + 7 \cdot 3i - 5i \cdot 2 - 5i \cdot 3i
\]
Step 2: Simplify the Terms
Calculate each term:
\(7 \cdot 2 = 14\)
\(7 \cdot 3i = 21i\)
\(-5i \cdot 2 = -10i\)
\(-5i \cdot 3i = -15i^2\)
Since \(i^2 = -1\), we have:
\(-15i^2 = 15\)
Step 3: Combine Like Terms
Combine the real and imaginary parts:
\[
14 + 15 + (21i - 10i) = 29 + 11i
\]
Final Answer
The standard form of \((7-5i)(2+3i)\) is \(\boxed{29 + 11i}\). Therefore, the answer is C.