Question 909572
x + 7x = 18.2
How is x + 7x  the same as {{{sqrt(x^2 + 7x) }}}   ?
x^2 + 7x = 330
x^2 + 7x - 330=0
Try to factor
Dismiss negative answers for measurements.
*[invoke change_this_name4450 1,7, -330, "x"]
If not use quadratic formula 
*[invoke quadratic "x", 1,7, -330,]