why matlab always show my equation as matrix dimension

i have tried to input the equation 
y = (668.061/x)*[-39-e^(-0.1468*x)]

, but it always says that

Error using  ^  (line 51)
Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a
scalar. To perform elementwise matrix powers, use '.^'.

Answer 1

[Birdman]

Try this:

y = (668.061./x)*[-39-exp(-0.1468*x)]

Answer 2

[Stephen23]

Most likely you need to follow the advice given in the error message and use array operations, e.g.:

y = (668.061./x).*(-39-exp(-0.1468*x))

"why matlab always show my equation as matrix dimension"

Because you used the wrong operators:

https://www.mathworks.com/help/matlab/matlab_prog/array-vs-matrix-operations.html