3 x + 7 = 2
3 x = 2 - 7
3 x = - 5
x = - 5/3
3 ( -5/3) + 7 = - 15/3 + 7 = - 5 + 7 = 2


if we were to place <5, 12> in standard position, so it'd be originating from 0,0, then the rise is 12 and the run is 5.
so any other vector that has a negative reciprocal slope to it, will then be perpendicular or "orthogonal" to it.
so... for example a parallel to <-12, 5> is say hmmm < -144, 60>, if you simplify that fraction, you'd end up with <-12, 5>, since all we did was multiply both coordinates by 12.
or using a unit vector for those above, then
Well I can explain how Ted is wrong. 3 tenths multiplied by 100 is actually 30. The place value of the three goes up 2 times and the decimal goes backward by 2.
You would do 1250 dived by 30.
1250/30 = 41.666
And if you round that, she would need 42 trays.
Hope I helped :)
D 50%, since the sections U and X took up 30 of the 60 spins which is half, which is 50%