Find the Standard Form of the Function: Transforming (x+4)² - 16

Quadratic Functions with Vertex Form Expansion

Find the standard representation of the following function

f(x)=(x+4)216 f(x)=(x+4)^2-16

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Simplified to the standard representation of the function
00:03 Open parentheses according to the shortened multiplication formulas
00:11 Calculate powers and products
00:24 Subtract
00:27 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Find the standard representation of the following function

f(x)=(x+4)216 f(x)=(x+4)^2-16

2

Step-by-step solution

To solve this problem, we'll follow these steps:

  • Step 1: Expand (x+4)2(x + 4)^2 using the formula (a+b)2=a2+2ab+b2(a + b)^2 = a^2 + 2ab + b^2.
  • Step 2: Simplify the expression by subtracting 16 from the expanded result.
  • Step 3: Write the simplified expression in the standard form.

Now, let's work through each step:
Step 1: Start with the expression given in the problem:
(x+4)2=x2+2x4+42 (x + 4)^2 = x^2 + 2 \cdot x \cdot 4 + 4^2 .

This results in:
x2+8x+16 x^2 + 8x + 16 .

Step 2: Subtract 16 from the expanded expression:
x2+8x+1616=x2+8x x^2 + 8x + 16 - 16 = x^2 + 8x .

Step 3: The standard form of the expression is now:
f(x)=x2+8x f(x) = x^2 + 8x .

Therefore, the standard representation of the function is f(x)=x2+8x f(x) = x^2 + 8x .

3

Final Answer

f(x)=x2+8x f(x)=x^2+8x

Key Points to Remember

Essential concepts to master this topic
  • Perfect Square Formula: Use (a+b)2=a2+2ab+b2 (a+b)^2 = a^2 + 2ab + b^2 to expand binomials
  • Technique: (x+4)2=x2+8x+16 (x+4)^2 = x^2 + 8x + 16 then subtract constant
  • Check: Verify by factoring x2+8x=x(x+8) x^2 + 8x = x(x+8) matches original vertex ✓

Common Mistakes

Avoid these frequent errors
  • Forgetting to subtract the constant term after expanding
    Don't stop after expanding (x+4)2=x2+8x+16 (x+4)^2 = x^2 + 8x + 16 and write that as your final answer = missing the -16! This gives x2+8x+16 x^2 + 8x + 16 instead of x2+8x x^2 + 8x . Always complete all operations in the original expression.

Practice Quiz

Test your knowledge with interactive questions

Create an algebraic expression based on the following parameters:

\( a=2,b=2,c=2 \)

FAQ

Everything you need to know about this question

What's the difference between vertex form and standard form?

+

Vertex form like (x+4)216 (x+4)^2 - 16 shows the vertex clearly, while standard form like x2+8x x^2 + 8x shows coefficients for graphing and calculations.

Why do I need to expand the perfect square?

+

Expanding helps you see the individual coefficients of x2 x^2 , x x , and constant terms. This makes it easier to add, subtract, or compare with other quadratic functions.

How do I remember the perfect square formula?

+

Think "First, Outer, Inner, Last" or remember the pattern: (a+b)2=a2+2ab+b2 (a+b)^2 = a^2 + 2ab + b^2 . The middle term is always twice the product of the two terms!

What if I get confused with the signs?

+

Work step by step! In (x+4)216 (x+4)^2 - 16 , first expand the square completely: x2+8x+16 x^2 + 8x + 16 , then subtract 16 at the very end.

Can I check my answer by plugging in a value?

+

Absolutely! Pick any x-value like x = 0. Check that both (0+4)216=0 (0+4)^2 - 16 = 0 and 02+8(0)=0 0^2 + 8(0) = 0 give the same result.

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Ways of Representing the Quadratic Function questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations