I know how to hack this app i learned it just take a jailbroken device install ifile go to
Var/mobile/applications/álgebra solver/library and open this archive:
com.euclidus.algbra.solver.plist
Só...now modify this words like this :
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>AnswerPackPurchaseKey</key>
<false/>
<key>FailedProblemCount</key>
<integer>0</integer>
<key>FreeAnswerLimit</key>
<integer>1</integer>
<key>FreeProblemSolverAddress</key>
<string>http://euclidus-algebra-4-3-free.appspot.com/solverserver</string>
<key>FreeSolutionLimit</key>
<integer>3</integer>
<key>InstalledVersion</key>
<integer>1029</integer>
<key>LegacyPremiumPackPurchaseKey</key>
<true/>
<key>PremiumProblemSolverAddress</key>
<string>http://euclidus-algebra-4-3.appspot.com/solverserver</string>
<key>ReviewPromptDone</key>
<true/>
<key>ReviewPromptSessionSequence</key>
<integer>0</integer>
<key>ReviewPromptSolvedProblemCount</key>
<integer>0</integer>
<key>SessionSequence</key>
<integer>5</integer>
<key>SolutionPackPurchaseKey</key>
<true/>
</dict>
</plist>
Ps.:where u have "false"put "true"
And Enjoy