Question

a为何值时,关于x的方程4x-3(x-3)=5x+3(a+6)的解:（1）是负数；（2）小于½；（3）不大于a

Answer 1

4x-3(x-3)=5x+3(a+6)

4x-3x+9=5x+3a+18;

4x=-3a-9;

x=(-3a-9)/4;

(1)3a+9＞0;

a＞-3;

(2)(-3a-9)/4＜1/2;

-3a-9＜2;

a＞-11/3;

(3)(-3a-9)/4≤-a;

-3a-9≤-4a;

a≤9;