若|a|=5 |b|=3 且a小于b 求3a+2b的值

\u5df2\u77e5x^a=3,x^b=5,\u6c42x^(3a-2b)\u7684\u503c.

\u5df2\u77e5x^a=3,x^b=5,
x^(3a-2b)
=x^3a/x^2b
=(x^a)^3/(x^b)^2
=(3^3)/(5^2)
=27/25

3/4a+1/2b=1/4(3a+2b)=6 \u6240\u4ee53/4a-5+1/2b=6-5=1

3a =-15 2b=6 所以最终结果是-9

∵a的绝对值等于5
∴a＝±5
∵b的绝对值等于3
∴b＝±3
∵a＜b
∴a＝﹣5 b＝3
3×﹙﹣5﹚＋2×3＝﹣9

-21或-9