简便运算、定义新运算.
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/08/25 23:06:10
简便运算、定义新运算.
简便:1、7.48+3.17-(2.48-6083)2、8.75-0.35+(1.25-6.65)3、7.6×1.75+17.5×0.24
定义新运算:a☆b=a+b-1,a○b=a×b-1求:若x☆(x○4)=30,x的值是多少?
简便:1、7.48+3.17-(2.48-6083)2、8.75-0.35+(1.25-6.65)3、7.6×1.75+17.5×0.24
定义新运算:a☆b=a+b-1,a○b=a×b-1求:若x☆(x○4)=30,x的值是多少?
1、6083应该为6.83
7.48+3.17-(2.48-6.83)
=7.48-2.48+3.17+6.83
=5+10
=15
2、8.75-0.35+(1.25-6.65)
=8.75+1.25-(0.35+6.65)
=10-7
=3
3、7.6×1.75+17.5×0.24
=7.6×1.75+1.75×2.4
=1.75×(7.6+2.4)
=1.75×10
=17.5
x☆(x○4)=x☆(4x-1)=x+4x-1-1=5x-2=30
5x=32
x=6.4
7.48+3.17-(2.48-6.83)
=7.48-2.48+3.17+6.83
=5+10
=15
2、8.75-0.35+(1.25-6.65)
=8.75+1.25-(0.35+6.65)
=10-7
=3
3、7.6×1.75+17.5×0.24
=7.6×1.75+1.75×2.4
=1.75×(7.6+2.4)
=1.75×10
=17.5
x☆(x○4)=x☆(4x-1)=x+4x-1-1=5x-2=30
5x=32
x=6.4