Question 1057887

​(a) For the parabola y= -5x^2+7x+1 find the vertex.
​(b) Does the vertex correspond to the highest point or the lowest point on the​ graph?
<pre>x-coordinate of vertex: {{{matrix(1,7, x = - b/(2a), "====>", x = - 7/(2 * - 5), "====>", x = (- 7)/(- 10), "====>", x = 7/10)}}}
y-coordinate of vertex: {{{matrix(1,11, y = - 5(7/10)^2 + 7(7/10) + 1, "====>", y = - 5(49/100) + 49/10 + 1, "====>", y = (- 245)/100 + 49/10 + 1, "====>", y = (- 245)/100 + 490/100 + 100/100, "======>", y = 345/100, "====>", y = 69/20)}}} ------ Substituting {{{7/10}}} for x in original equation
Vertex of parabola: {{{highlight_green(matrix(1,5, "(", 7/10, ",", 69/20, ")"))}}}
As indicated by the LEADING coefficient being < 0, the parabola opens downward and will have a MAXIMUM vertex, which is its highest point.