Question 36336
Factor the expression:
{{{6x^2-42x+72}}} First factor out a 6.
{{{6(x^2-7+12)}}} Now factor the parentheses.
{{{6(x-3)(x-4)}}}

To find the roots, you must have an "equation". So presumably, you mean this expression to be equal to zero.
{{{6x^2-42x+72 = 0}}} Now we can find the roots. Factor as above.
{{{6(x-3)(x-4) = 0}}} Apply the zero products principle. 6 is not zero, so:
{{{(x-3)(x-4) = 0}}} Apply the zero products principle again.
{{{x-3 = 0}}} and/or {{{x-4 = 0}}}
If {{{x-3 = 0}}} then {{{x = 3}}}
If {{{x-4 = 0}}} then {{{x = 4}}}

The roots are:
x = 3
x = 4