vvnre a Slope-Intercept equation ror a line mat passes rnrougn l 1.\" arm 12, a). To write the slope-intercept equation. rst find the slope. Note that the slope m of a line containing points (x1. v1) and 1'2 'Y1 , ' ' n m= . (12 mils 9W3 by x2 _x1 5'2 '3'1 Considsrlts 1,?) as (11, 3(1) and (2, *5) as (x2. ya). Substitute 1 form. 3' for Y1- 2 for x2, and -5 for 3,02 in m= x x . 2 1 Y2 \"Y1 m = x2 \"'1 = 3 Substitute the values form. n, x2. and v2. 2( 1} = -4 Simplify. Therefore. the slope of the line is m = - 4. Now use the slope-intercept equation to nd the yintercept. If m is the slope and {Up} is the y-intercept. then the slope-intercept equation is given by v = mx + b. Substitute - d for m and {2, - 5) for (x, y) in y = mx + b and solve for b. y = mx + b - 5 = (- 4). (2)+ b Substitute the values for rn. x, and v. 5= B+b Multiply. Add 8 on both sides. 5= B+b 5+a= a+b+a Add. a=b Simplify. Next substitute 4form and3forbiny=mx+b. y= -4x+3 Thus. the slope-intercept equation of the line that passes through (- 1,7) and (2. - 5} is y = -4x + 3