Question 39681
Factorise:
{{{4x^2-49}}}
Notice that the given expression is the difference of two squares:
{{{(2x)^2 - (7)^2}}}

The difference of two squares is factorable:
{{{A^2-B^2 = (A-B)(A+B)}}}

Applying this to your expression, we have:
{{{4x^2-49 = (2x-7)(2x+7)}}}