### Home > CCA > Chapter 2 > Lesson 2.3.2 > Problem2-91

2-91.

Find the equation of the line that goes through the points (–15, 70) and (5, 10). 2-91 HW eTool (Desmos). Homework Help ✎.

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One strategy is to graph the two points and make a slope triangle to find the slope of the line.

Use the slope triangle to find the slope of this line.

$m=\frac{\Delta y}{\Delta x}=\frac{-60}{20}$

Substitute a pair of coordinates for x and y and the slope to solve for b.
y = mx + b
10 = −3(5) + b
10 = −15 + b
25 = b

Substitute the values found for m and b into the equation of the line.