Use the table to answer the question.

System A System B

7x+4y=−4

5x+8y=28



7x+4y=−4

?

Which of the following terms will make the systems equivalent?


(1 point)
Responses

−12x−12y=24

negative 12 x minus 12 y equals 24
−14x−8y=8
negative 14 x minus 8 y equals 8
12x+12y=24
12 x plus 12 y equals 24
−14x−8y=−8

1 answer

To determine which equation will make System B equivalent to System A, we first need to manipulate the equation from System A to see what form it takes.

We have:

  1. System A: \[ 7x + 4y = -4 \]

We should check the second equation in System B to see how it relates to System A.

  1. System B: \[ 5x + 8y = 28 \]

Now we can manipulate the equation from System B to see if we can find a relationship to the first equation from System A.

We can put both equations in a similar standard form \(Ax + By = C\) to see if they're equivalent:

  1. Multiply System A equation by a scalar if needed, to reach similar coefficients with System B.
  2. Rearrange System B equation: Multiply the first equation \(7x + 4y = -4\) by 2 to match the variables better.

Multiplying: \[ 2(7x + 4y) = 2(-4) \implies 14x + 8y = -8 \]

Now, we have:

  • Transformed System A: \[ 14x + 8y = -8 \]

Now we look at all the given choices to find which is equal to \(14x + 8y = -8\) after suitable manipulation:

  1. Check the first option: \[ -12x - 12y = 24 \] Rewriting this: \[ 12x + 12y = -24 \quad \text{(not equivalent)} \]

  2. Check the second option: \[ -14x - 8y = 8 \] Rewriting this: Multiplying by \(-1\): \[ 14x + 8y = -8 \quad \text{(equivalent)} \]

  3. Check the third option: \[ 12x + 12y = 24 \] (not equivalent)

  4. Check the fourth option: \[ -14x - 8y = -8 \] Rewriting this: Multiplying by \(-1\): \[ 14x + 8y = 8 \quad \text{(not equivalent)} \]

The only choice that is equivalent or can be manipulated to match \[14x + 8y = -8\] is:

\[ \boxed{-14x - 8y = 8} \]