3.3 point-slope form

Question

Find an equation for the line perpendicular to the line 9x+3y=−39x+3y=−3 having the same y-intercept as −7x+4y=2−7x+4y=2.

Answer 1

9x+3y=-3

y=-3x-1 has slope =-3

perpendicular line has a negative inverse slope = 1/3

-7x+4y=2

y=7x/4+1/2 has y intercept=1/2

y=(1/3)x +1/2 is the perpendicular line with intercept same as 2nd line in slope intercept form

when a linear equation is solved for y, the coefficient of the x term is the slope, and the constant term is the y intercept