70) perpendicular means you take the number in from of the x and flip it and switch the sign. that number will become your slope (m). y=mx+b. plug in slope and point -5=(7/9)(-4)+b. multiply -5=(-28/9)+b. add over -28/9 b= -17/9. plug b and slope into original equation y=(7/9)x+(-17/9) get rid of frac by multi by 9 (y=(7/9)x+(-17/9))*9 9y=7x+-17. subtract over 7x -7x+9y=-17. answer
Same goes for the rest. number 72 the perp slope will be (1/3) and for 74 the answer will be x=-5 (that is a weird case)
