question 4i in practice problems 1

i think q6b also has a problem, answer would be -9 and 5 instead of 9 and 5, could be wrong tho

also 3d the eq of the perpendicular line is y= (x/3)+3 i think

6b) you are correct it should be x=-9, and x=5

3d) the equation of the perpendicular line is y= (-x/3)+1. The slope is going to the be opposite reciprocal of the original slope. The initial slope is 3, so the perpendicular slope would be -1/3