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At graph of Number 4: Let's first determine the equation of each line.
LINE 1: Let's use point A: (x1,y1) = (-5,-5) and point B: (x2,y2) = (-3,-4).
Getting the slope (m):
[tex]\text{ m = }\frac{y_2-y_1_{}}{x_2-x_1}[/tex][tex]\text{ m = }\frac{-4\text{ - (-5)}}{-3\text{ - (-5)}}\text{ = }\frac{-4\text{ + 5}}{-3\text{ + 5}}\text{ = }\frac{1}{2}[/tex]Getting the y-intercept (b): Use m = 1/2 and x,y = -5,-5
[tex]\text{ y = mx + b}[/tex][tex]-5\text{ = (}\frac{1}{2})(-5)\text{ + b}[/tex][tex]\text{ -5 = }\frac{-5}{2}\text{ + b }\rightarrow\text{ b = -5 + }\frac{5}{2}[/tex][tex]\text{b = }\frac{\text{-10}}{2}\text{ + }\frac{5}{2}\text{ = }\frac{-10\text{ + 5}}{2}[/tex][tex]\text{ b = -}\frac{5}{2}[/tex]Let's complete the equation: Substitute m and b in y = mx + b.
[tex]\text{ y = mx + b}[/tex][tex]\text{ y = (}\frac{1}{2})x\text{ + (-}\frac{5}{2})[/tex][tex]\text{ y = }\frac{1}{2}x\text{ - }\frac{5}{2}\text{ ; f(x) = }\frac{1}{2}x\text{ - }\frac{5}{2}[/tex]LINE 2: Let's use point A: (x1,y1) = (-3,-2) and point B: (x2,y2) = (1,0).
Getting the slope (m):
[tex]\text{ m = }\frac{y_2-y_1}{x_2-x_1}[/tex][tex]\text{ m = }\frac{0-(-2)}{1-(-3)}=\frac{0\text{ + 2}}{1\text{ + 3}}\text{ = }\frac{2}{4}\text{ = }\frac{1}{2}[/tex]Getting the y-intercept (b): Use m = 1/2 and x,y = 1,0
[tex]\text{ y = mx + b}[/tex][tex]\text{ 0 = (}\frac{1}{2})(1)\text{ + b}[/tex][tex]\text{ 0 = }\frac{1}{2}\text{ + b}[/tex][tex]\text{ b = -}\frac{1}{2}[/tex]Let's complete the equation: Substitute m and b in y = mx + b.
[tex]\text{ y = mx + b}[/tex][tex]\text{ y = (}\frac{1}{2})x\text{ + }(-\frac{1}{2})[/tex][tex]\text{ y = }\frac{1}{2}x\text{ - }\frac{1}{2}\text{ ; f(x) = }\frac{1}{2}x\text{ - }\frac{1}{2}[/tex]LINE 3: Let's use point A: (x1,y1) = (1,2) and point B: (x2,y2) = (3,3).
Getting the slope (m):
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