Solve for X: -7/4(-x) + 2x - 5(x+3) = -x Linear Equation

Linear Equations with Negative Fraction Distribution

74(x)+2x5(x+3)=x -\frac{7}{4}(-x)+2x-5(x+3)=-x

x=? x=\text{?}

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1

Understand the problem

74(x)+2x5(x+3)=x -\frac{7}{4}(-x)+2x-5(x+3)=-x

x=? x=\text{?}

2

Step-by-step solution

To solve the given linear equation 74(x)+2x5(x+3)=x -\frac{7}{4}(-x) + 2x - 5(x + 3) = -x , follow these steps:

  • Step 1: Distribute the coefficients across the terms within parentheses:
    The term 74(x) -\frac{7}{4}(-x) becomes 74x \frac{7}{4}x because 74×x=74x -\frac{7}{4} \times -x = \frac{7}{4}x .
    The term 5(x+3) -5(x + 3) can be expanded to 5x15 -5x - 15 .
  • Step 2: Simplify the equation by combining like terms:
    The equation becomes 74x+2x5x15=x \frac{7}{4}x + 2x - 5x - 15 = -x .
  • Step 3: Combine the x x -terms on the left side:
    Combine: 74x+2x5x \frac{7}{4}x + 2x - 5x .
    Converting all terms to a common denominator, 2x=84x 2x = \frac{8}{4}x and 5x=204x -5x = \frac{-20}{4}x . Thus,
    74x+84x204x=54x \frac{7}{4}x + \frac{8}{4}x - \frac{20}{4}x = \frac{-5}{4}x .
  • Step 4: The equation simplifies to:
    54x15=x \frac{-5}{4}x - 15 = -x .
  • Step 5: Isolate the x x terms onto one side:
    Add x x to both sides, treating x -x as 44x \frac{-4}{4}x :
    54x+x15=0 \frac{-5}{4}x + x - 15 = 0 , which simplifies to 14x15=0 \frac{-1}{4}x - 15 = 0 .
  • Step 6: Isolate x x :
    Add 15 15 to both sides:
    14x=15 \frac{-1}{4}x = 15 .
  • Step 7: Solve for x x :
    Multiply both sides by 4 -4 to isolate x x :
    x=15×4 x = 15 \times -4 .
    Thus, x=60 x = -60 .

Therefore, the solution to the equation is x=60 x = -60 .

3

Final Answer

60 -60

Key Points to Remember

Essential concepts to master this topic
  • Distribution: Multiply negative signs carefully to avoid sign errors
  • Technique: 74(x)=+74x -\frac{7}{4}(-x) = +\frac{7}{4}x because negative times negative equals positive
  • Check: Substitute x = -60: 74(60)+2(60)5(60+3)=60 \frac{7}{4}(-60) + 2(-60) - 5(-60+3) = -60

Common Mistakes

Avoid these frequent errors
  • Incorrectly handling negative signs during distribution
    Don't distribute 74(x) -\frac{7}{4}(-x) as 74x -\frac{7}{4}x = wrong sign throughout! This creates the wrong coefficients and leads to incorrect solutions. Always remember that negative times negative equals positive, so 74(x)=+74x -\frac{7}{4}(-x) = +\frac{7}{4}x .

Practice Quiz

Test your knowledge with interactive questions

Solve for \( b \):

\( 8-b=6 \)

FAQ

Everything you need to know about this question

Why does 74(x) -\frac{7}{4}(-x) become positive?

+

Because you're multiplying two negatives! The rule is: negative × negative = positive. So 74×(x)=+74x -\frac{7}{4} \times (-x) = +\frac{7}{4}x .

How do I combine fractions with whole numbers like 74x+2x \frac{7}{4}x + 2x ?

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Convert everything to the same denominator! Write 2x 2x as 84x \frac{8}{4}x , then add: 74x+84x=154x \frac{7}{4}x + \frac{8}{4}x = \frac{15}{4}x .

What if I get a really big negative number like -60?

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Don't worry! Large answers are normal in algebra. The important thing is that your solution process is correct. Always substitute back to verify your answer works.

Can I solve this without fractions by multiplying everything by 4 first?

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Yes! Multiply every term by 4 to clear the fraction: 7x+8x20x60=4x 7x + 8x - 20x - 60 = -4x . This often makes the arithmetic easier.

How do I check such a complicated equation?

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Substitute x=60 x = -60 into the original equation and calculate each part step by step. If both sides equal the same number, you're correct!

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