Pei-Hsin Lin 林培心 🌸

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3. Need explanation for a math question

Thanks for catching that, Lynn.

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3. Need explanation for a math question

If you think about it in terms of money, two debts put together make an even bigger debt. (-3)³ - 4² =-27 - 16 =-27 + (-16) = -43 The answer would be 11 if the problem were slightly different. (3)³...

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3. Arithmetic Sequence

The explicit formula for arithmetic sequences always follows a specific format. The xth term aᵪ is always equal to the first term a₁ plus the common difference d (x - 1) times: aᵪ = a₁ + d(x - 1) I...

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3. Inverse Fucntions

Ah, now we're delving into calculus. If f(x) is restricted to the domain (-1,1) and the range (-∞,∞), then f⁻¹(x) is restricted to the domain (-∞,∞) and the range (-1,1). Restriction to the range (...

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3. Inverse Fucntions

STEP 1 For a given f(x), set f(x) = y. STEP 2 Isolate x in terms of y. STEP 3 Set x = f⁻¹(y). Note that this process does not always yield a function. Many rational functions are not invertible. If...

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3. Quadratics (again; please help!)

Hi Bailey, Use the distributive property in reverse here. Factor out the 3 in both terms of the numerator. 3 ÷ 3 = 1. Any number divided by itself equals 1. The simplified result is just all that's...

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2. SAT Questions and Feedback
3. Amazing SAT Practice but not enough Question-Specific Material

Hi Matthew, For help with specific problems, just post your question and the Khan Academy community will try to help you. As for the question you have mentioned: Medicine (M) in milligrams is given...

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2. Content Requests and Feedback
3. new feature for maths

Hi Max! If I understand correctly, you're asking for a specialized widget for drawing line segments, similar to what's available in MS Paint or Adobe Photoshop. In case they don't implement your fe...

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2. Content Requests and Feedback
3. No Statistics and Probability Mastery Challenge?

Hi Arnaud, You're right - Math by Subject > Statistics & Probability doesn't link to a regular mission with Mastery Challenges. I've noticed this, too! But Math by Grade > High School does point to...

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3. Absolute value equation graphs

You're welcome, Alex! 👍