Solve the Rational Equation: Finding X in (6+x)/(x+5) = 4/11

Cross-Multiplication with Rational Equations

Solve for X:

6+xx+5=411 \frac{6+x}{x+5}=\frac{4}{11}

❤️ 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 Find X
00:05 Multiply by denominators to eliminate fractions
00:21 Simplify as much as possible
00:36 Carefully open parentheses properly, multiply by each term
00:51 Arrange the equation so that X is isolated on one side
01:08 Combine like terms
01:20 Isolate X
01:31 Simplify as much as possible
01:34 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

Solve for X:

6+xx+5=411 \frac{6+x}{x+5}=\frac{4}{11}

2

Step-by-step solution

To solve the given equation 6+xx+5=411\frac{6+x}{x+5}=\frac{4}{11}, follow these steps:

  • Step 1: Use cross-multiplication to eliminate the fractions. Multiply 11(6+x) 11(6 + x) and 4(x+5) 4(x + 5) across the equation:

11(6+x)=4(x+5) 11(6 + x) = 4(x + 5)

  • Step 2: Expand both sides of the equation:

66+11x=4x+20 66 + 11x = 4x + 20

  • Step 3: Isolate x x by first eliminating the smaller x x term. Subtract 4x 4x from both sides:

66+11x4x=20 66 + 11x - 4x = 20

66+7x=20 66 + 7x = 20

  • Step 4: Further simplify to isolate x x . Subtract 66 from both sides:

7x=2066 7x = 20 - 66

7x=46 7x = -46

  • Step 5: Solve for x x by dividing both sides by 7:

x=467 x = \frac{-46}{7}

x=6.57 x = -6.57

Therefore, the solution to the equation is \textbf{\( x = -6.57 } \).

3

Final Answer

6.57 -6.57

Key Points to Remember

Essential concepts to master this topic
  • Cross-Multiplication Rule: Set products of diagonals equal: (6+x)(11) = 4(x+5)
  • Distribution Technique: Expand to 66 + 11x = 4x + 20 carefully
  • Verification Check: Substitute x = -46/7 back into original equation both sides equal ✓

Common Mistakes

Avoid these frequent errors
  • Forgetting to distribute after cross-multiplication
    Don't write 11(6+x) = 66x instead of 66 + 11x = wrong coefficient! This creates an incorrect linear equation with the wrong solution. Always distribute each factor completely: 11(6+x) = 66 + 11x.

Practice Quiz

Test your knowledge with interactive questions

Solve for X:

\( x - 3 + 5 = 8 - 2 \)

FAQ

Everything you need to know about this question

Why can't I just multiply both sides by (x+5)?

+

You could, but cross-multiplication is more efficient when you have one fraction equal to another fraction. It eliminates both denominators in one step!

What if x+5 equals zero in my answer?

+

Great question! If your solution makes the denominator zero, that answer is invalid. Always check that x ≠ -5 in this problem, since that would make the fraction undefined.

How do I handle the decimal answer -6.57?

+

The exact answer is 467 \frac{-46}{7} . You can leave it as a fraction or convert to decimal. Both forms are correct, but fractions are often preferred for exact values.

Can I check my work without substituting back?

+

Substitution is the best verification method, but you can also check your algebra steps. Make sure your cross-multiplication and distribution are correct at each step.

What if I get a positive answer instead?

+

Double-check your signs! When you get 7x=46 7x = -46 , dividing by positive 7 gives a negative result. Sign errors are very common in multi-step problems.

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Linear Equations (One Variable) 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