Question

Find approximate x-intercepts,
y=-5x^2+7x+8

Answer 1

you can find the x intercepts by setting y to zero. that will leave you with a quadratic equation to solve for x.

Answer 2

\[5x ^{2}-7x-8=0\]

Answer 3

yup - just solve that to find two value for x.

Answer 4

So? \[7+\sqrt{209}/10\]

Answer 5

that is ONE of the x intercepts. remember that there are two solutions (the square root of a number can be plus/minus).
see here for solution of this quadratic: http://www2.wolframalpha.com/input/?i=5x%5E2-7x-8%3D0