Answer:
pretty sure it's 56 I could be wrong though
To make that graph you follow these steps.
1) Set the cartesian coordinate system:
- vertical axis: y
- horizontal axis: x
- positive x-semi axis: to the right
- negative x-semi axis: to the left
- positive y-semi axis: upward
- negative y semi axis: dwonward
2) solve the inequality for y:
given: -2x + 5y > 15
transpose-2x: 5y > 15 + 2x
divide by 5: y > 3 + (2/5)x
3) Graph-
draw the line y = 3 + (2/5)x, using a dotted line (i.e. - - - - - -)
- remember that 3 is the y intercept, and 2/5 is the slope
- the line is dotted because
the solution does not include the points in the line.
- the solution is the
region above and to the left of the dotted line.
4) See the
figure attached for better visualization: the pink region is the solution of the inequality.
The number of positive and negative roots or zeros of a polynomial function is predicted through the Descartes Rule of Sign. This was first described by Rene Descartes in his work La Geometrie. The technique is for determining an upper bound on the number of positive and negative real roots.