The line with equation y=mx+6 has a slope, m, such that m[2,12]. Use an interval to describe the possible x-intercepts of the line? Please explain in detail how to get the answer.

1 Answer
Feb 22, 2018

[12,3]

Explanation:

Consider the high and low values of the slope to determine the high and low value of the x-int. Then we can phrase the answer as an interval.

High:
Let m=12:
y=12x+6
We want x when y=0, so
0=12x+6
12x=6
x=12

Low:
Let m=2
Likewise:
0=2x+6
2x=6
x=3

Therefore the range of x-ints is 12 to 3, inclusive.

This is formalized in interval notation as:
[12,3]

PS:
Interval notation:
[x,y] is all values from x to y inclusive
(x,y) is all values from x to y, exclusive.
(x,y] is all values from x to y excluding x, including y
...
"[" means inclusive, "(" means exclusive.
Note: is always exclusive. so x3 is [3,)