Problem: Linear functions and the delta-notation

Problem

A linear function has slope $a=7/3$ .

1. If $x$ increases by one unit ( $Δx=1$ ), find the increase in $y$ (find $Δy$ )
2. If $x$ increases by nine units ( $Δx=9$ ), find the increase in $y$ (find $Δy$ )
3. If $x$ decreases by one unit ( $Δx=-1$ ), find the increase in $y$ (find $Δy$ )
4. If $x$ decreases by nine units ( $Δx=-9$ ), find the increase in $y$ (find $Δy$ )
5. You know that the increase in $y$ was $9/2$ ( $Δy=-9$ ). What was the increase in $x$ ? (find $Δx$ )

(A negative increase is the same as a decrease)