Answer
a) $\dfrac{1}{2}$
b) If $x$ increases by $2$ units, then $y$ increases by $1$ unit.
Work Step by Step
We know that by the Slope Formula: if $P_1(x_1,y_1)$ and $P_2(x_2,y_2)$ are on a line, then the slope is: $m=\dfrac{y_2-y_1}{x_2-x_1}$.
a) Use the formula above to find the slope and have:: $m=\dfrac{1-0}{2-0}=\dfrac{1}{2}.$
b) A slope of $\dfrac{1}{2}$ means that if $x$ increases by $2$ units, then $y$ increases by $1$ unit.