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Zorluk: Çok zorLinear Equations in One Variable
If xx satisfies the linear equation
3x142x+35=x34+25\frac{3x - 1}{4} - \frac{2x + 3}{5} = \frac{x - 3}{4} + \frac{2}{5}
what is the value of 4x34x - 3?
  1. A
    5
  2. B
    13
  3. 17Cevap
  4. D
    57
  5. E
    77

Cevap

17
Solving the equation by grouping terms with like denominators gives 2x+24=2x+55\frac{2x + 2}{4} = \frac{2x + 5}{5}. Simplifying the left side to x+12\frac{x + 1}{2} and cross-multiplying yields 5(x+1)=2(2x+5)5(x + 1) = 2(2x + 5), which simplifies to 5x+5=4x+105x + 5 = 4x + 10, giving x=5x = 5. Evaluating 4x34x - 3 at x=5x = 5 produces 4(5)3=174(5) - 3 = 17, making this answer correct.

Adım Adım Çözüm

1
Group like fractional terms with denominator 4 on one side and denominator 5 on the other side of the equation.
\frac{3x - 1}{4} - \frac{x - 3}{4} = \frac{2x + 3}{5} + \frac{2}{5}
Grouping terms with common denominators simplifies algebraic combination.
2
Combine the numerators over their common denominators, carefully distributing signs.
\frac{(3x - 1) - (x - 3)}{4} = \frac{(2x + 3) + 2}{5} \implies \frac{2x + 2}{4} = \frac{2x + 5}{5}
Subtracting (x3)(x - 3) requires distributing the negative sign to yield x+3-x + 3.
3
Simplify the left side fraction and cross-multiply to eliminate denominators.
\frac{x + 1}{2} = \frac{2x + 5}{5} \implies 5(x + 1) = 2(2x + 5)
Simplifying 2x+24\frac{2x+2}{4} to x+12\frac{x+1}{2} reduces computation before cross-multiplication.
4
Expand both sides and solve for xx.
5x + 5 = 4x + 10 \implies 5x - 4x = 10 - 5 \implies x = 5
Subtracting 4x4x and 55 from both sides isolates xx.
5
Substitute x=5x = 5 into the required expression 4x34x - 3.
4(5) - 3 = 20 - 3 = 17
The question asks for the value of 4x34x - 3, not xx alone.

Anahtar Kavram

Solving linear equations in one variable involving fractional terms and evaluating targeted algebraic expressions.
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