No.153 Finding a Linear Function from Two Points
POINT
First find the slope using \(a=\dfrac{y_2-y_1}{x_2-x_1}\). Then substitute either point into \(y=ax+b\).
Example
1
Find the equation of the line through \( (1,2) \) and \( (3,8) \).
\(y=3x-1\)
2
Find the equation of the line through \( (2,-5) \) and \( (6,-3) \).
\(y=\frac12x-6\)
TRY
TRY 1
Through \( (0,1) \) and \( (2,5) \).
\(y=2x+1\)
TRY 2
Through \( (-1,4) \) and \( (2,-5) \).
\(y=-3x+1\)
TRY 3
Through \( (1,2) \) and \( (5,4) \).
\(y=\frac12x+\frac32\)
TRY 4
Through \( (-2,3) \) and \( (4,1) \).
\(y=-\frac13x+\frac73\)