Question 13949
You had everything right as far as you went, but...
When you got to:

{{{0.8x^2 = 26.2}}} and you correctly divided both sides by 0.8, you should have got:
{{{x^2 = 32.75}}} not {{{x = 32.75}}}, so now you have to take the square root of both sides to find x.

{{{x = sqrt(32.75)}}}
{{{x = 5.72276}}} approximately.