Which of the following shows a system of equations equivalent to 2x + 7y=14 and 4x + 5y=10?

A. 4x+14y=28 and 8x+10y=10
B. 4x+14y=14 and 4x+5y=10
C. 2x+7y=14 and 2x+5y=5
D. 2x+7y=14 and 8x+10y=20

1 answer

To determine which option shows a system of equations equivalent to the given equations \(2x + 7y = 14\) and \(4x + 5y = 10\), we can manipulate each equation or check each provided option for equivalence.

  1. Starting equations: \[ 2x + 7y = 14 \quad (1) \] \[ 4x + 5y = 10 \quad (2) \]

  2. Multiply equation (1) by a factor (for example, by 2): \[ 2(2x + 7y) = 2(14) \implies 4x + 14y = 28 \quad (3) \]

  3. Multiply equation (2) by a factor (for example, by 2): \[ 2(4x + 5y) = 2(10) \implies 8x + 10y = 20 \quad (4) \]

Now, let's analyze each answer option to see if they match the forms we've acquired or are equivalent in some way:

A. \(4x + 14y = 28\) and \(8x + 10y = 20\)

  • \((3)\) and \((4)\) are correct.

B. \(4x + 14y = 14\) and \(4x + 5y = 10\)

  • The first equation is not equivalent since it should be \(4x + 14y = 28\).

C. \(2x + 7y = 14\) and \(2x + 5y = 5\)

  • The first equation is correct, but the second is not equivalent to \(4x + 5y = 10\).

D. \(2x + 7y = 14\) and \(8x + 10y = 20\)

  • The first is correct, and the second is equivalent since it comes from multiplying \(4x + 5y = 10\) by 2.

Thus, the equivalent systems of equations that match our transformations are:

A. \(4x + 14y = 28\) and \(8x + 10y = 20\)
D. \(2x + 7y = 14\) and \(8x + 10y = 20\)

Since only one option can be chosen and \(D\) shows one of the original equations, the best answer is:

D. \(2x + 7y = 14\) and \(8x + 10y = 20\)