$P=82kN$

$=2k\frac{N}{m}$

$82kN,$

$R_A+R_B-4KN-82KN=0$

$R_A+R_B=86KN$

$(41)-(RB2)+(824)=0$

$4-(RB2)+328=0$

$+(RB2)=+332$

$RB=166kN$

$R_A=86-166KN$

$R_A=-80kN$

make me understand its SFD and BMD daigram i am getting confused when my reaction force at a is negative how does and SFD starts.