Solve the absolute value equation |12−3x|=|9+4x| .(1 point)

Responses

x=−21 and x=37
x equals negative 21 and x equals Start Fraction 3 over 7 End Fraction

x=37 and x=3
x equals Start Fraction 3 over 7 End Fraction and x equals 3

x=4
x equals 4

no solution
no solution

1 answer

To solve the equation \( |12 - 3x| = |9 + 4x| \), we need to consider the different cases for absolute values.

We can break this down into four cases based on the expressions inside the absolute values.

Case 1:

\( 12 - 3x = 9 + 4x \)

Solving this: \[ 12 - 3x = 9 + 4x \] \[ 12 - 9 = 4x + 3x \] \[ 3 = 7x \] \[ x = \frac{3}{7} \]

Case 2:

\( 12 - 3x = -(9 + 4x) \)

Solving this: \[ 12 - 3x = -9 - 4x \] \[ 12 + 9 = -4x + 3x \] \[ 21 = -x \] \[ x = -21 \]

Case 3:

\( -(12 - 3x) = 9 + 4x \)

Solving this: \[ -12 + 3x = 9 + 4x \] \[ -12 - 9 = 4x - 3x \] \[ -21 = x \] This is a repeated solution, so we will only take \( x = -21 \).

Case 4:

\( -(12 - 3x) = -(9 + 4x) \)

Solving this: \[ -12 + 3x = -9 - 4x \] \[ -12 + 9 = -4x - 3x \] \[ -3 = -7x \] \[ x = \frac{3}{7} \] This is a repeated solution, so we will only take \( x = \frac{3}{7} \).

Summary of Solutions

The solutions we found are:

  • \( x = -21 \)
  • \( x = \frac{3}{7} \)

Thus the answers to the equations \( |12 - 3x| = |9 + 4x| \) are:

  • \( x = -21 \)
  • \( x = \frac{3}{7} \)

The correct response is: x equals negative 21 and x equals Start Fraction 3 over 7 End Fraction.