1. You are given PR and RS, so simply add the two measurements to get PS.
28.2+30.7= 58.9
2. Subtract QV from QT to get TV.
78-56= 22
3. Again, Subtract QV from QT to get TV.
74-36= 38
4. Similar to question 1, add PR and RS to get PS.
40+53= 93
By using the rule -b/2a —> 12/-6= -2