先化简再求值:(5x+7)(2x-3)-(10x-1)(x-2)其中x=-1/2

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/03 07:09:10
先化简再求值:(5x+7)(2x-3)-(10x-1)(x-2)其中x=-1/2

先化简再求值:(5x+7)(2x-3)-(10x-1)(x-2)其中x=-1/2
先化简再求值:(5x+7)(2x-3)-(10x-1)(x-2)其中x=-1/2

先化简再求值:(5x+7)(2x-3)-(10x-1)(x-2)其中x=-1/2
(5x+7)(2x-3)-(10x-1)(x-2)其中x=-1/2
=10x²-15x+14x-21-10x²+20x+x-2
=20x-23
=20×(-1/2)-23
=-10-23
=-33;
很高兴为您解答,skyhunter002为您答疑解惑
如果本题有什么不明白可以追问,


(5x+7)(2x-3)-(10x-1)(x-2)
=10x²-15x+14x-21-(10x²-20x-x+2)
=10x²-x-21-10x²+21x-2
=20x-23
=20×(-1/2)-23
=-10-23
=-33

(5x+7)(2x-3)-(10x-1)(x-2)
=10x²-x-21-(10x²-21x+2)=20x-23
x=-1/2带入
20x-23=20×(-1/2)-23=-33
满意望采纳,不懂可追问·

(5x+7)(2x-3)-(10x-1)(x-2)=10x^2-x-21-10x^2+21x-3
=20x-24
=-34