A^2-ab-5a+5b при а=1 /4,b=-1/2

Question

A^2-ab-5a+5b при а=1 /4,b=-1/2

Answer 1

A²-ab-5a+5b=a(a-b)-5(a-b)=(a-b)(a-5)=(1/4+1/2)(1/4-5)=-(3/4*19/4)=-57/16