No typed explanation or matlab please

Use Householder's method to place the following matrices in tridiagonal form.

d$.[[4\mathrm{.}75,2\mathrm{.}25,-0\mathrm{.}25],[2\mathrm{.}25,4\mathrm{.}75,1\mathrm{.}25],[-0\mathrm{.}25,1\mathrm{.}25,4\mathrm{.}75]]$