Positive and negative intervals

A coordinate plane. The x-axis scales by one, and the y-axis scales by ten. The graph of the function y equals f of x is below the x-axis from x equals negative five to x equals one. It is above the x-axis from x equals one to x equals four. It is below the x-axis after x equals four. The function decreases from x equals negative five to x equals negative two and one-half. It increases from x equals negative two and one-half to x equals two and one-half. It decreases after x equals two and one-half. All values are estimates.