|-2x +5|=|5x + 7|

Mathematiques1 réponse
Réponse de Bryon
Equation with Absolute Values

Solve the equation: | -2x + 5 | = | 5x + 7 |

When we have an absolute value equation like this, it means the two expressions inside the absolute value can be equal or opposites.

So, we consider two cases:


Case 1:

Set the expressions equal:

-2x + 5 = 5x + 7

Let's solve for x:

  • Subtract 5x from both sides: -2x - 5x + 5 = 7
  • -7x + 5 = 7
  • Subtract 5 from both sides: -7x = 2
  • Divide both sides by -7: x = 2 / -7
  • So, x = -2/7

Case 2:

Set the expressions equal with opposite signs:

-2x + 5 = - (5x + 7)

which simplifies to:

-2x + 5 = -5x - 7

Let's solve for x:

  • Add 5x to both sides: -2x + 5x + 5 = -7
  • 3x + 5 = -7
  • Subtract 5 from both sides: 3x = -12
  • Divide both sides by 3: x = -12 / 3
  • So, x = -4

Final answer:

Solutions are x = -2/7 and x = -4.

Une question qui te bloque ?

Crée ton compte gratuitement pour poser tes propres questions et réviser avec Bryon.