Special topic: calculation problems.
Analysis: Substitute x=-3, y=- 1 into the second equation of the system of equations, x=5, y=4 into the first equation of the system of equations, and find out the values of A and B at the same time, thus finding out the value of the formula.
Answer: Solution: Will
x=？ three
y=？ 1
Substituting 4x-by=-2 in the equation gives:-12+b=-2, that is, b =10;
will
x=5
y=4
Substituting ax+5y= 15 in the equation gives 5a+20= 15, that is, a=- 1.
Then the original formula = 1- 1 = 0.
Comments: This question examines the solution of a binary linear equation. The solution of the equation is an unknown number that can make two equations in the equation hold.
references/Math/QUES/Detail/df 3 EC 8 b 2-8b 72-4A7E-838 1-74e 7483089 F4