f(x) = -x + 3

g(x) = 4

h(x) = 5x/4

I(-1;4)

J(3,2;4)

K(1,3;1,7)

f(x) = g(x)

-x+3 = 4

x = -1

h(x) = g(x)

5x/4 = 4

x = 16/5 = 3,2

f(x) = h(x)

-x+3=5x/4

xK = 12/9 = 4/3

h(4/3) = yK = 5/3

En espérant t'avoir aidé.