X f πxf
-1 2 -2
3 1 3
-1 -2 2
0 -3 0
total =3
mean (π)=πxf ÷n
= 3÷4
= 0.75 these is not answer I thank so
Answer:

Step-by-step explanation:




Step-by-step explanation:
tanA=8/15 and tan B=40/9
tan(A+B)=(tanA+tanB)/1-tanAtanB
(8/15+40/9)/1-(8/15×40/9)
=-672/185