math
posted by Kelli on .
solve the polynomial ineqaality. express the solution set in interval notation.
x^3+x^2+64x+64>0

332

ss33

x^3+x^2+64x+64>0
x^2(x+1) + 64(x+1) > 0
(x+1)(x^2 + 64) > 0
since x^2 + 64 is always positive
we just have to look at
x+1 > 0
x > 1
see
http://www.wolframalpha.com/input/?i=x%5E3%2Bx%5E2%2B64x%2B64
notice the graph is > 0 (above the xaxis) for all values of x , x >1
The first graph looks like a straight line, but it isn't.
the scaling distorts the graph.