How do I plot blue asterisks on the x and y intercepts of a linear function on a 2D graph?

%cartesian plane
p = [-20,20];
q = p-p;

hold on;
plot(p,q);
plot(q,p);
grid on;

% getting the function from the user.
y = input("Introduce a linear function : ");

Unable to run the 'fevalJSON' function because it calls the 'input' function, which is not supported for this product offering.

ezplot(y);
% now how do i plot blue asterisks on the x and y intercepts of the
% function the user just introduced?

Answer 1

[Chunru]

% getting the function from the user.
% ystr = input("Introduce a linear function a*x+b: ", "s");   

ystr ="3*x -6";
y = str2func("@(x)" + ystr);

xintercept = fsolve(y, 0);

Equation solved.

fsolve completed because the vector of function values is near zero
as measured by the value of the function tolerance, and
the problem appears regular as measured by the gradient.

yintercept = y(0);

fplot(y)
hold on
xline(0, 'r'); yline(0, 'r');
plot(xintercept, 0, 'b*');
plot(0, yintercept, 'b*');
grid on