1 A rectangular picture frame has perimeter 70 cm.
a The width of the frame is x cm. Find an
expression, in terms of x, for the height
of the frame.
b Find an equation for the area of the
frame, Acm?, in terms of x.
c Plot the graph which shows how A
varies with x. Use a suitable domain and
range. Hence sketch the graph on paper.
d Find the x-intercepts of the graph in part c.
e State what these two values of x represent.
f Hence find the equation of the graph's
line of symmetry, and state what this
tells you in the context of the problem.