Question 473418
{{{h = 6x^2 - 56.8x + 228}}}
If h ever goes below 80 then the crocodile will catch her.
Find minimum value and test to see if it is greater than 80.
Minimum value of an upward parabola is at the vertex.
To find x_coordinate of vertex, {{{x = (-b)/2a}}} where a,b,c are the coefficients 6,-56.8,228
{{{x = (-(-56.8))/(2*6) = 56.8/12 = 4.73}}}
Now find the corresponding height at x=4.73
{{{h = 6(4.73^2) - 56.8(4.73) + 228}}}
{{{h = 134.24 - 268.66 + 228}}}
{{{h = 93.6}}}
Therefore since minimum height is 93.6, at no point will she fall below 80 and it is safe to jump