Use the graph to shorten the list of possible rational zeros of the function. Then find all real zeros of the function.
1.) f(x)= 4x^3-8x^2-15x+9
4.) f(x)= 2x^3-5x^2-4x+10
3 answers
who knows how to do this?
checking the graphs at wolframalpha.com,
http://www.wolframalpha.com/input/?i=4x^3-8x^2-15x%2B9
http://www.wolframalpha.com/input/?i=2x^3-5x^2-4x%2B10
it is clear that
#1 has a root at x = 3
#2 has a root at x = 5/2
So, divide through and you can use the quadratic formula to find the other roots.
http://www.wolframalpha.com/input/?i=4x^3-8x^2-15x%2B9
http://www.wolframalpha.com/input/?i=2x^3-5x^2-4x%2B10
it is clear that
#1 has a root at x = 3
#2 has a root at x = 5/2
So, divide through and you can use the quadratic formula to find the other roots.
the answer is wherever the graph hits the x axis.
1. -3/4, 1/2, 3
2. -3/2, 3/2, 5/2
1. -3/4, 1/2, 3
2. -3/2, 3/2, 5/2