OK yall i need help with this.I honestly hate geometry.Seriously.I need good student with good explanation skills.Ill mark brainlest and up my points!

Answer:
Step-by-step explanation:
In parallelogram, opposite sides are parallel and equal
3x + 7 = 5x -17
3x - 5x = -17 - 7
-2x = - 24
x = -24 /-2
x = 12