Q. Solve the Equation: \( -3(x – 14) + 9x = 6x + 42 \)

Answer

  1. Expand the left side.

    Distribute the -3.

    \[ -3x + 42 + 9x = 6x + 42 \]

  2. Combine like terms.

    \[ 6x + 42 = 6x + 42 \]

  3. Isolate x.

    Subtract 6x from both sides.

    \[ 42 = 42 \]

  4. Conclusion.

    This is an identity. Every real number satisfies the equation.

    \[ x \in \mathbb{R} \]

Detailed Explanation

Problem: Solve the equation \( -3(x – 14) + 9x = 6x + 42 \).

  1. Distribute (use the distributive property):

    Multiply \(-3\) by each term inside the parentheses \( (x – 14) \).

    Computation: \( -3(x – 14) = -3\cdot x + (-3)\cdot(-14) = -3x + 42 \).

    After distribution the equation becomes \( -3x + 42 + 9x = 6x + 42 \).

  2. Combine like terms on the left-hand side:

    Combine the \(x\)-terms \(-3x\) and \(9x\): \( -3x + 9x = 6x \).

    So the left-hand side simplifies to \(6x + 42\), giving the equation \( 6x + 42 = 6x + 42 \).

  3. Compare both sides and attempt to isolate the variable:

    Subtract \(6x\) from both sides to try to isolate \(x\):

    Computation: \( 6x + 42 – 6x = 6x + 42 – 6x \) which yields \( 42 = 42 \).

    Alternatively, subtract \(42\) from both sides to obtain \( 6x = 6x \) and then \( 0 = 0 \) after subtracting \(6x\); both lead to a true identity.

  4. Conclusion about solutions:

    Because the equation simplifies to a true statement that does not involve \(x\) (for example \(42 = 42\) or \(0 = 0\)), the original equation is an identity: it is true for every real number \(x\).

    Therefore the solution set is all real numbers, written as \( \mathbb{R} \) or \( (-\infty, \infty) \).

  5. Quick verification (optional):

    Pick any value of \(x\), for example \(x = 0\):

    Left side: \( -3(0 – 14) + 9\cdot 0 = -3(-14) + 0 = 42.\)

    Right side: \( 6\cdot 0 + 42 = 42.\)

    Both sides match, consistent with the conclusion that every real \(x\) satisfies the equation.

Final answer: All real numbers (solution set \( \mathbb{R} \) or \( (-\infty, \infty) \)).

See full solution
image
Master linear equations with AI homework help.
AI homework helper

Frequently Asked Questions

What is the solution to -3(x - 14) + 9x = 6x + 42?

All real numbers. After simplifying both sides you get 6x + 42 = 6x + 42, which is always true, so every real x satisfies the equation (infinitely many solutions).

How do I distribute the -3 correctly?

Multiply each term inside the parentheses: -3(x - 14) = -3x + 42. The negative sign multiplies both x and -14.

Why do I combine 9x and -3x?

They are like terms (both contain x). Combining 9x + (-3x) gives 6x, which simplifies the equation and helps isolate variables.

How can I tell there are infinitely many solutions instead of one or none?

If all variable terms cancel and you end with true identity (like 42 = 42), the equation holds for every x. false statement (like 5 = 3) would mean no solution.

How do I check my answer is correct?

Substitute any number for x (e.g., x = 0 or x = 10) into the original equation; if both sides are equal for every choice, the solution set is all real numbers.

What common mistakes should I watch for?

Forgetting to distribute the negative sign, combining unlike terms, sign errors when moving terms, or dividing by zero erroneously. Check each distribution and arithmetic step.

What's the graphical interpretation?

The equation represents two identical lines (same slope and intercept), so their graphs coincide and intersect at infinitely many points.

Is subtracting 6x from both sides valid step?

Yes. Subtracting the same expression from both sides is an algebraically valid operation and preserves the solution set; it leads here to the true statement 42 = 42.
Explore smart apps today.
Start building now! :)
image
173,935+ happy customers
Math, Calculus, Geometry, etc.
top
Upgrade to Edubrain Premium
Unlimited help across all subjects
$16
$3.99
/week
Core benefits:
  • ok Unlimited AI homework help
  • ok A+ quality answers
  • ok Faster responses, no limits
Tools:
  • ok Notes generator
  • ok Diagram generator
  • ok AI detector and humanizer
Extras:
  • ok Ad-free experience
  • ok Share responses with others
  • ok Advanced reasoning
expert
Expert-level help at discounted prices
Cancel anytime
Star
4.6Trusted by 14,623 students
🚀 Upgrade Plan
You’ve reached the free limit of 5 slides.
To generate a full presentation, please subscribe.
Unlock with subscription:
  • ok Unlimited slide generation for presentations
  • ok AI-designed, well-structured slide content
  • ok Faster workflow for bigger decks
-
Plus, get unlimited access to:
  • ok Diagram Generator, Flashcard Maker, Notes Generator, Research Assistant, Answer Generator, AI Homework Helper & AI Detector
  • ok Discounted designer expert help
Star
4.6Trusted by 14,623 students