Question 1103113
y=0;
solve for x.

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Finding x-intercepts:
Let y=0 and solve for x.
You could or should general solution for quadratic equation.  Just follow the formula and solve for x in  {{{-x^2+24x+64=0}}}; or factorize if possible.


Finding y-intercept:
Just let x=0 and solve for y.  That will be your y-intercept.
This is not more than simple substitution, as in  {{{y=-0^2+24*0+64}}}.