2018 l2 calculus Exam
So the smallest area the parallelogram can have is when x = 4.5 cm. This gives an area of
2 x 4.5 x 4.5 - (18 x 4.5) +80
= 39.5 cm squared.
2 x 4.5 x 4.5 - (18 x 4.5) +80
= 39.5 cm squared.
Remember that at the vertex of the parabola or maximum point the slope is zero, so the line must pass through -1 on the x axis where y = 0. I know you are not asked for any further evidence but you could work out the value of k, hence the equation of the parabola. This could be differentiated to find the equation of the line either in factored form or expanded form. (See below).
But that would be asking too much for an achieved question.