Question

求下列各式的值,

3X²-(2x²+5x-1﹚-﹙3x+1﹚,其中x=10 ﹙xy-3/2y-1/2﹚-﹙xy-3/2x+1﹚其中X=3/10 y=8/3 4y²-﹙x²+y﹚+﹙x²-4y²﹚ 其中x=-28 y=18 求代数式的值 5xˆ4+3x²y+xˆ4-1 p²+2pq+6-8p²+pq ﹙7y-3z﹚-﹙8y-5z﹚ ﹣﹙aˆ5-6b)-(-7+sb) 2(2a²+9b﹚+3﹙-5a²-4b﹚ -3﹙2x²-xy﹚+4﹙x²+xy-6﹚

Answer 1

3X²-(2x²+5x-1﹚-﹙3x+1﹚
=3x²-2x²-5x+1-3x-1
=x²-8x
=100-80
=20

﹙xy-3/2y-1/2﹚-﹙xy-3/2x+1﹚
=xy-3/2y-1/2-xy+3/2x-1
=3/2x-3/2y-3/2
=9/10-4-3/2
=-23/5

4y²-﹙x²+y﹚+﹙x²-4y²﹚
=4y²-x²-y+x²-4y²
=-y
=-18

5xˆ4+3x²y+xˆ4-1
=6x^4+3x²y-1

p²+2pq+6-8p²+pq
=-7p²+3pq+6

﹙7y-3z﹚-﹙8y-5z﹚

=7y-3z-8y+5z
=-y+2z

﹣﹙aˆ5-6b)-(-7+sb)
=﹣aˆ5+6b+7-sb

2(2a²+9b﹚+3﹙-5a²-4b﹚
=4a²+18b-15a²-12b
=-11a²+6b

-3﹙2x²-xy﹚+4﹙x²+xy-6﹚
=-6x²+3xy+4x²+4xy-24
=-2x²+7xy-24