Weighted average problems

I think they should fix this because the only solution I found was to uninstall and reinstall the app, super awesome, and last it has photomath you just snap a picture and it will give the answer, i purchased this for my daughter in 8th grade, also there's no ads to disturb us! :D 10/10 Oh and uh it also has a manual calculator with all sorts of stuff.

I'm a student of class 8(ICSE board), it's pretty user friendly there is not a problem that I have found that is can't solve. This app saved my college life, this app does really good solution but there are times that Im not sure of its solution example when I entered the equation x²+x=272 there is this part that says write x as the difference and I cant understand where on earth did it get -17x+16x.

Take a pic of the problem and its calculated for you right away. This app is amazing I love everything about it. Good so far, just wish I could see each step for each of problem without having to pay anything, or at least a Free trial would help.