P \[=116.58\div 8.7=13.4\] Q \[=15.06-9.18=5.88\] R \[=912.06-418.05=494.01\] So, \[R-P\times Q=494.01-13.4\times 5.88\] \[=\TEXT{ }494.01-78,792=415.218\]