当自变量x的取值满足什么条件时,函数y=5x+17的值满足下列条件?
问题描述:
当自变量x的取值满足什么条件时,函数y=5x+17的值满足下列条件?
(1)y=0
(2)y=-7
(3)y=20
答
(1)y=0
5x+17=0
5x=-17
x=-17/5
(2)y=-7
5x+17=-7
5x=-7-17
5x=-24
x=-24/5
(3)y=20
5x+17=20
5x=20-17
5x=3
x=3/5