Question

How would I figure out a linear equation with two plot points with fractions? (1/3(6),3) and (1/2(19),-2) are my two plot points. I was able to graph them on Desmos, but I can't seem to figure out how I would go about figuring out the slope and y-intercept in this case... the fractions are what's throwing me off here. Please help!

Answer 1

Answer: $m=\frac{-30}{79},\ y=5.40$

Step-by-step explanation:

Given

Points are $\left(6\frac{1}{3},3\right),\ \left(19\frac{1}{2},-2\right)$

Convert mixed numeral to fraction

$\left(6\frac{1}{3},3\right)\Rightarrow \left(\dfrac{19}{3},3\right)\\\\\left(19\frac{1}{2},-2\right)\Rightarrow \left(\dfrac{39}{2},-2\right)$

Slope of the line is

$\Rightarrow m=\dfrac{3-(-2)}{\dfrac{19}{3}-\dfrac{39}{2}}\\\\\Rightarrow m=\dfrac{5}{\dfrac{38-117}{6}}\\\\\Rightarrow m=\dfrac{-30}{79}$

Equation of line

$\Rightarrow \dfrac{y-3}{x-\dfrac{19}{3}}=\dfrac{-30}{79}\\\\\text{for y-intercept, put x=0}\\\\\Rightarrow \dfrac{y-3}{0-\dfrac{19}{3}}=\dfrac{-30}{79}\\\\\Rightarrow y-3=\dfrac{190}{79}\\\\\Rightarrow y=3+2.40\\\Rightarrow y=5.40$