Given are the two points A(-2,4) and B(3,b).
He wants to draw a line with slope equal to zero.
We know the slope formula for two points is given as follows :-
[tex]Slope = \frac{y_{2}- y_{1} }{x_{2} -x_{1} } \\\\ Slope \;of A(-2,4) \;and \;B(3,b) \\\\ Slope \;AB = \frac{b-4}{3-(-2)} \\\\ Slope \;AB = \frac{b-4}{3+2)} \\\\ Slope \;AB = \frac{b-4}{5} \\\\ given \;slope \;of \;AB = 0 \\\\ 0 = \frac{b-4}{5} \\\\ 0 = b-4 \\\\ b = 4[/tex]
Hence, b=4 is the final answer.
