Above is the graph of the quadratic function $y=a{x}^2+bx+c$ where a, b and c are constants. Using the graph, find :
(a)(i) the scales on both axes ; (ii) the equation of the line of symmetry of the curve ; (iii) the roots of the quadratic equation $a{x}^2+bx+c=0$
(b) Use the coordinates of D, E and G to find the values of the constants a, b and c hence write down the quadratic function illustrated in the graph.
(c) Find the greatest value of y within the range $-3\le x\le 5$.


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