来自秦向阳的问题
【(5X-5)(2X+3)-2(3X-5)(4X-1)当A=1/3时,求(A-4)(A-3)-(A-1)(A-3)的值】
(5X-5)(2X+3)-2(3X-5)(4X-1)
当A=1/3时,求(A-4)(A-3)-(A-1)(A-3)的值
1回答
2020-02-25 16:29
【(5X-5)(2X+3)-2(3X-5)(4X-1)当A=1/3时,求(A-4)(A-3)-(A-1)(A-3)的值】
(5X-5)(2X+3)-2(3X-5)(4X-1)
当A=1/3时,求(A-4)(A-3)-(A-1)(A-3)的值
(5X-5)(2X+3)-2(3X-5)(4X-1)
=(10X^2+15X-10X-15)-2(12X^2-3X-20X+5)
=(10X^2+5X-15)-2(12X^2-23X+5)
=10X^2+5X-15-24X^2+46X-10
=-14X^2+51X-25
当A=1/3时,(A-4)(A-3)-(A-1)(A-3)=(1/3-4)(1/3-3)-(1/3-1)(1/3-3)=8