OG详解-OG8 数学1 Q13

The correct answer is 25. Subtracting the second equation from the first equation in the given system of equations yields (2a-2a)+(8b-4b)= 198-98, which is equivalent to 0+4b = 100, or 4b = 100. Dividing each side of this equation by 4 yields b = 25.