I need help on number six and seven. I have no clue how to do it can someone explain?

an

y = 6x -3y -12

y +3y +12 = 6x

=> . x = { 2y / 3 +2 } this is equation of line in terms of x

=> . if line meets the x-axis the co-ordinates of meeting point would be ( x , 0 )

=> . x = 2 ( 0 ) / 3 + 2

=> . x = 2

so, the point is ( 2 , 0 )

you need to rotate this triangle about the origin 270 degrees clockwise to create the full square.

the answer is 15 to your question