A line's slope-intercept form, , uses the slope and the -value at . A given point with supplies directly, so write the rule and evaluate it in Desmos at the requested input. Keep the slope's sign: a negative slope makes decrease as increases.
Hints
- Hint 1
A -intercept is the point on a line where . Since the given point has input , which number is the line's -value at that input?
- Hint 2
In slope-intercept form , the slope tells you how changes when increases by . The slope here is negative. What rule combines it with the value at ?
Step-by-step
Write the line, then evaluate it
Step 1Build the line's rule
In slope-intercept form , is the slope and is the -value when . The point gives because its input is . Use the given slope to write the rule:
- Step 2
Enter the rule in Desmos
A function is a rule that gives an output for an input. Name this line's rule by typing in Desmos. It stores the same line so you can evaluate it at the requested input.
- Step 3
Find the output at the requested input
Type on the next line. This means put in for , and Desmos displays . The negative slope makes the output fall as increases, so don't change its sign. When , the line has . Grid in -2.