What is the equation of the line that passes through the points (−2, 1) and (1, 10)?
a. 3x − y = −7
b. 3x − y = −5
c. 3x − y = 5
d. x + 3y = −5

One way is subsitution, but that's no fun

use
y-y1=m(x-x1)
a point is (x1,y1)) and the slope is m
so slope between the oints (-2,1) and (1,10) is
(10-1)/(1-(-2))=9/(1+2)=9/3=3

a point is (1,10)
y-10=3(x-1)
exapand
y-10=3x-3
solve for constant
minus 3 both sides and add 10
y-3x=7
times -1
3x-y=-7

A is answer