Which o the following pairs of equation has exactly the same solution?

3/8x = 1 and 1/3x = 1/8

-3.2x = 0.64 and z/4 = 0.05

z/3.2 = 1.8 and 1.8x = 3.2

-3/4x = 5/4 and 5/2x = -3/4

1 answer

To determine which pairs of equations have exactly the same solution, we can solve each equation in the pairs and compare their solutions.

Pair 1:

  1. \( \frac{3}{8}x = 1 \) \[ x = 1 \cdot \frac{8}{3} = \frac{8}{3} \]

  2. \( \frac{1}{3}x = \frac{1}{8} \) \[ x = \frac{1}{8} \cdot 3 = \frac{3}{8} \]

Solutions:

  • First equation: \( x = \frac{8}{3} \)
  • Second equation: \( x = \frac{3}{8} \)
  • Not the same solution.

Pair 2:

  1. \( -3.2x = 0.64 \) \[ x = \frac{0.64}{-3.2} = -0.2 \]

  2. \( \frac{z}{4} = 0.05 \) \[ z = 0.05 \cdot 4 = 0.2 \]

Solutions:

  • First equation: \( x = -0.2 \)
  • Second equation: \( z = 0.2 \)
  • Not the same solution.

Pair 3:

  1. \( \frac{z}{3.2} = 1.8 \) \[ z = 1.8 \cdot 3.2 = 5.76 \]

  2. \( 1.8x = 3.2 \) \[ x = \frac{3.2}{1.8} \approx 1.78 \]

Solutions:

  • First equation: \( z = 5.76 \)
  • Second equation: \( x \approx 1.78 \)
  • Not the same solution.

Pair 4:

  1. \( -\frac{3}{4}x = \frac{5}{4} \) \[ x = \frac{5}{4} \cdot -\frac{4}{3} = -\frac{5}{3} \]

  2. \( \frac{5}{2}x = -\frac{3}{4} \) \[ x = -\frac{3}{4} \cdot \frac{2}{5} = -\frac{3}{10} \]

Solutions:

  • First equation: \( x = -\frac{5}{3} \)
  • Second equation: \( x = -\frac{3}{10} \)
  • Not the same solution.

None of the pairs have the same solution.