What is the real part of (6 + 5i)(3 - 4i)?
Answer
38
Reasoning Strategy
Distribute and replace i^2 with -1.
AI Support Preview
Flag the imaginary-by-imaginary product as the sign-changing term.
Public Practice Guide
Use this guide to see the type of reasoning MathRoutine expects for grade 10 complex numbers worksheet with answers. The goal is not worksheet volume; it is helping students read the situation, choose a model, and explain why the answer fits.
What Students Practice
Reasoning Patterns
Sample Problems
These grade-specific examples show the kind of student-visible reasoning MathRoutine is designed to support: identifying the important quantities, choosing the right structure, and checking the final answer against the story.
What is the real part of (6 + 5i)(3 - 4i)?
Answer
38
Reasoning Strategy
Distribute and replace i^2 with -1.
AI Support Preview
Flag the imaginary-by-imaginary product as the sign-changing term.
Two alternating-current signals are represented by 5 + 7i and 3 - 2i. What is their sum?
Reasoning Strategy
Combine real parts and imaginary parts separately.
AI Support Preview
Keep the two components labeled instead of adding unlike terms.
A system multiplies the complex factors 4 + 3i and 2 - 5i. What is the real part of the product?
Reasoning Strategy
Use distribution and replace i^2 with -1.
AI Support Preview
Flag the imaginary-by-imaginary product as the sign-changing step.
The quadratic x^2 - 6x + 13 models a design constraint. What does the discriminant show about real solutions?
Reasoning Strategy
Calculate b^2 - 4ac and interpret a negative result.
AI Support Preview
Connect a negative discriminant to no real x-intercepts.
Two signals are represented by 6 + 4i and 9 - 2i. When they are added, what is the real part?
Reasoning Strategy
Combine only the real parts for the requested component.
AI Support Preview
Prevent mixing real and imaginary components in one sum.
A model multiplies 3 + 5i and 7 + 2i. What is the real part of the product?
Reasoning Strategy
Use ac - bd for the real part because i squared is negative one.
AI Support Preview
Highlight the imaginary-by-imaginary product as the common sign trap.
For x^2 + 10x + 34, what is the discriminant b^2 - 4ac?
Reasoning Strategy
Substitute a = 1, b = 10, c = 34 and evaluate carefully.
AI Support Preview
Connect the negative discriminant to complex roots without requiring a formula jump.
Add 7 + 4i and 3 - 9i.
Answer
10 - 5i
Reasoning Strategy
Combine real parts and imaginary parts separately.
AI Support Preview
Keep the two components labeled.
Keep Practicing
Practice 1000+ more problems with grade-fit AI support.
Practice Ladder
Modeled after Algebra 1/Algebra 2 workbook expectations: interpret a function or equation in context, solve or compare it, then justify the meaning of the answer.
Translate the language into a mathematical relationship.
Solve while tracking constraints, units, and intermediate quantities.
Check whether the solution makes sense in the original context.
Assessment Signals
A guide is useful only if it clarifies what teachers and parents should look for in student work. MathRoutine tracks these signals during practice instead of treating every miss as the same mistake.
Common Mistakes
Learning Loop
A strong word problem platform should not only say right or wrong. It should notice the pattern: missed unit rate, ignored leftover, reversed comparison, wrong base percent, or equation setup error.
1
Attempt
2
Diagnosis
3
Next practice
Diagnosis Examples
Each word problem should create evidence about setup, calculation, vocabulary, hidden quantities, or final-question confusion. These examples show what MathRoutine is designed to separate after an attempt.
If the attempt shows
The student combines real and imaginary terms as if they were like terms.
Likely diagnosis
Component tracking is weak.
Next practice
Use complex-number context prompts that require separate real and imaginary parts.
If the attempt shows
The student forgets that i squared equals negative one.
Likely diagnosis
The defining imaginary-unit relationship is not stable.
Next practice
Practice powers and products of i inside short modeling contexts.
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