Proportionality>Determining Rate of Change and Y-Intercept from Data Tables and Graphs(TEKS.Math.8.4.C)
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Texas 8th Grade Math › Proportionality>Determining Rate of Change and Y-Intercept from Data Tables and Graphs(TEKS.Math.8.4.C)
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1
Points on a line: $(1, 2)$, $(3, 8)$, $(5, 14)$, $(7, 20)$
Which pair shows the slope and $y$-intercept $(m, b)$ for this line?
(2, 3)
(-1, 3)
(3, -1)
(1, 3)
Explanation
Compute slope with any two points, say $(1,2)$ and $(3,8)$: $m=\frac{8-2}{3-1}=\frac{6}{2}=3$. Use $b=y-mx$ with $(1,2)$: $b=2-3(1)=-1$. So $(m,b)=(3,-1)$.