若2(x-1)=5-3(x+1),求式子13-3x^2-[7x-4(4x-3)+2x^2]的值

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/10 19:12:48
若2(x-1)=5-3(x+1),求式子13-3x^2-[7x-4(4x-3)+2x^2]的值

若2(x-1)=5-3(x+1),求式子13-3x^2-[7x-4(4x-3)+2x^2]的值
若2(x-1)=5-3(x+1),求式子13-3x^2-[7x-4(4x-3)+2x^2]的值

若2(x-1)=5-3(x+1),求式子13-3x^2-[7x-4(4x-3)+2x^2]的值
2(x-1)=5-3(x+1),
2x-2=5-3x-3
2x-2=2-3x
2x+3x=2+2
5x=4
x=4/5
13-3x^2-[7x-4(4x-3)+2x^2]
=13-3x^2-7x+4(4x-3)-2x^2
=13-5x^2-7x+4(4x-3)
=13-5x^2-7x+16x-12
=-5x^2+9x+1
=-5*(4/5)^2+9*(4/5)+1
=-16/5+36/5+1
=5

5