Question

先化简，在求值：（2a-3)(3a+1)-6a(a-4),其中a=2/17

Answer 1

（2a-3)(3a+1)-6a(a-4)
=6a²-7a-3-6a²+24a
=17a-3
=2-3
=-1

Answer 2

解：（2a-3)(3a+1)-6a(a-4)
=6a²+2a-9a-3-6a²+24a
=17a-3
当a=2/17时，17a-3=17*2/17-3=-1
原式=-1

Answer 3

（2a-3)(3a+1)-6a(a-4)=6a^2-9a+2a-3-6a^2+24a=17a-3=2/17*17-3=-1