(4x + 1)(3x - 7) - (3x - 4)(2x - 8)

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Understand the Problem

The question is asking to simplify the expression (4x + 1)(3x - 7) - (3x - 4)(2x - 8). This involves applying the distributive property to expand each part of the expression and then combining like terms.

Answer

The simplified expression is \( 6x^2 + 7x - 39 \).
Answer for screen readers

The simplified expression is ( 6x^2 + 7x - 39 ).

Steps to Solve

  1. Expand the first expression: (4x + 1)(3x - 7)

Using the distributive property (also known as the FOIL method for binomials):

$$ (4x + 1)(3x - 7) = 4x \cdot 3x + 4x \cdot (-7) + 1 \cdot 3x + 1 \cdot (-7) $$

Calculating each part:

  • $4x \cdot 3x = 12x^2$
  • $4x \cdot (-7) = -28x$
  • $1 \cdot 3x = 3x$
  • $1 \cdot (-7) = -7$

So, combining these gives:

$$ 12x^2 - 28x + 3x - 7 = 12x^2 - 25x - 7 $$

  1. Expand the second expression: (3x - 4)(2x - 8)

Again using the distributive property:

$$ (3x - 4)(2x - 8) = 3x \cdot 2x + 3x \cdot (-8) + (-4) \cdot 2x + (-4) \cdot (-8) $$

Calculating each part:

  • $3x \cdot 2x = 6x^2$
  • $3x \cdot (-8) = -24x$
  • $-4 \cdot 2x = -8x$
  • $-4 \cdot (-8) = 32$

So, combining these gives:

$$ 6x^2 - 24x - 8x + 32 = 6x^2 - 32x + 32 $$

  1. Subtract the second expression from the first

Now we combine the two expanded expressions from the previous steps:

$$ (12x^2 - 25x - 7) - (6x^2 - 32x + 32) $$

Distributing the negative sign:

$$ 12x^2 - 25x - 7 - 6x^2 + 32x - 32 $$

  1. Combine like terms

Combine the terms:

  • For $x^2$ terms: $12x^2 - 6x^2 = 6x^2$
  • For $x$ terms: $-25x + 32x = 7x$
  • For constant terms: $-7 - 32 = -39$

So, putting them all together gives:

$$ 6x^2 + 7x - 39 $$

The simplified expression is ( 6x^2 + 7x - 39 ).

More Information

This expression represents a quadratic polynomial, which can be graphed as a parabola. Quadratic functions have various applications, including physics for describing projectile motion.

Tips

  • Forgetting to distribute the negative sign: When subtracting the second expression, it's crucial to distribute the negative sign to all terms.
  • Combining like terms incorrectly: Ensure that only like terms are combined together.

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