Question

初中数学X(X=1)-(X*X-Y)=-3.求(X*X+Y)/2+XY的值

Answer 1

X(X+1)-(X*X-Y)=-3

X²+X-X²+Y=-3

X+Y=-3

(X*X+Y*Y)/2+XY=(X*X+Y*Y+2XY)/2=(X+Y)²/2=(-3)²/2=9/2