a=

B = (2.18, 1.56)
A = Intersect(xAxis, yAxis)
l = Line(A, B)
m = Slope(l)
a = 0.7155963302752293
inputBox1 = Textfield(a)
mx = If(x(B) ≟ 0, NaN, y(B) / x(B))
f(x) = m * x
text1: "$f(x)=" + (LaTeX[f]) + "$"