We are given the graph of the function `f(x)=-x^2-3x+10 ` and we are asked to find the points a,b, and c as indicated on the graph.
Note that a and b are the x-intercepts, while c is the y-intercept.
(1) c is the easiest to find: the y-intercept occurs when x=0. Then f(0)=10, so the point c is at (0,10).
(2) The x-intercepts can be found in a few different ways. Since the quadratic function has x-intercepts, then the roots or zeroes of the function are real (and the same as the x-intercepts.) So we can factor the function (if possible) or use completing the square or the quadratic formula to find the roots.
`-(x^2+3x-10)=0 `
`-(x+5)(x-2)=0 ==> x=-5, x=2 `
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Thus a=(-5,0), b=(2,0), and c=(0,10)
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The graph:
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