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)