Question

2x-3y/3x+y=2,求代数式(4x-6y/9x+3y)+(18x+6y/4x-6y)的值

Answer 1

(4x-6y)/(9x+3y)+(18x+6y)/(4x-6y)

=2(2x-3y)/3(3x+y)+6(3x+y)/2(2x-3y)

=2/3*2+6/2*1/2=17/6

PS 事实上,除号和分数线可以理解为一回事

y=0.5x+12

设A树买了x棵,那么B树是（2000-x）棵

根据题意,得

0.95x+0.99(2000-x)=1960

x=500

所以 总费=500*(15+3)+(2000-500)*(20+4)=45000