Solve each given equation and show your work. Tell whether it has one solution, an infinite number of solutions, or no solutions, and identify each equation as an identity , a contradiction, or niether.

(a) 6x + 4x - 6 + 24 + 9x
(b) 25 - 4x + 15 - 3x + 10 - x
(c) 4x + 8 = 2x + 7 +2x -20

answer:

1 answer

Let's solve each equation step by step:

(a) \(6x + 4x - 6 + 24 + 9x\)

  1. Combine like terms: \[ 6x + 4x + 9x - 6 + 24 = (6x + 4x + 9x) + (-6 + 24) \] \[ = 19x + 18 \]

Since this expression is not set equal to anything, we interpret \(6x + 4x - 6 + 24 + 9x = 0\), which simplifies to: \[ 19x + 18 = 0 \]

  1. Solve for \(x\): \[ 19x = -18 \] \[ x = -\frac{18}{19} \]

Since we found a single solution, the answer has one solution and is classified as neither an identity nor a contradiction.


(b) \(25 - 4x + 15 - 3x + 10 - x\)

  1. Combine like terms: \[ 25 + 15 + 10 - 4x - 3x - x = (25 + 15 + 10) + (-4x - 3x - x) \] \[ = 50 - 8x \]

Again, interpret expression as equaling zero (\(50 - 8x = 0\)): \[ 50 - 8x = 0 \]

  1. Solve for \(x\): \[ -8x = -50 \] \[ x = \frac{50}{8} = \frac{25}{4} \]

This gives us one solution and is classified as neither an identity nor a contradiction.


(c) \(4x + 8 = 2x + 7 + 2x - 20\)

  1. Simplify the right-hand side: \[ 2x + 7 + 2x - 20 = (2x + 2x) + (7 - 20) \] \[ = 4x - 13 \]

So the equation becomes: \[ 4x + 8 = 4x - 13 \]

  1. Subtract \(4x\) from both sides: \[ 8 = -13 \]

This is a contradiction because \(8\) cannot equal \(-13\). Thus, the equation has no solutions and is classified as a contradiction.


Summary:

  • (a) One solution: \(x = -\frac{18}{19}\) (Neither)
  • (b) One solution: \(x = \frac{25}{4}\) (Neither)
  • (c) No solution (Contradiction)