x1 = 140
y1 = 70
x2 = 210
y2 = 270
x3 = 200
y3 = 200
x4 = 150
y4 = 270

a = (y2-y1)/(x2-x1)
b = y1 - a*x1

aprime = (y4-y3)/(x4-x3)
bprime = y3 - aprime*x3 

xp = (bprime - b)/(a - aprime)
yp = a*xp + b

printf("Coordonnées du point d''intersection P :\n")
printf("xp = %0.2f%s%0.2f\n",xp," et yp = ",yp)
