Need help with number 12

Answer:
x=70
Step-by-step explanation:
https://www.symbolab.com/solver/step-by-step/-%5Cfrac%7B3%7D%7B%205%7Dx-%5Cfrac%7B7%7D%7B10%7Dx%2B%5Cfrac%7B1%7D%7B2%7Dx%3D-56?or=input
this is a legit site that will show how they got the answer. I use it all the time.