How have interest rates changed over the past few generations

This policy changes by increased the supply of assets that available for investors and ,the real interest rate has been declined over the past few year generation caused of likelihood of financial instability,and the likelihood that the economy will run into the lower bound on nominal interest rates

The answer is: y would equal 3 because if you simplify the equation then it would be y= 3x+9 and if you divide 3x and 9 by 3 it would equal 3. y= 3