How to define cross points for two graphs

Hello, I have a problem to find cross points of two graphs. Here it is my script: x_1=[-3 2 4 7 9]; x_2=[-4 -1 3 6 8]; y_1=[2 6 5 8 3] y_2=[-1 6 8 8 7] xx_1=-3:0.01:9 yy_1=spline(x_1,y_1,xx_1) plot(xx_1,yy_1) grid on xx_2=-4:0.01:8; yy_2=spline(x_2,y_2,xx_2) plot(xx_1,yy_1,'--',xx_2,yy_2,'-') grid on axis equal. How can I define all cross points for these graphs numerically?

Sergey