x^2 + 9x^2
----------- = 16
(x + 3)^2
multiply each term by (x + 3)^2:-
x^2(x + 3)^2 + 9x^2 = 16(x + 3)^2
x^2( x^2 + 6x + 9) + 9x^2 = 16x^2 + 96x + 144
x^4 + 6x^3 + 18x^2 = 16x^2 + 96x + 144
x^4 + 6x^3 + 2x^2 - 96x - 144 = 0
This is difficult to solve algebraically so I drew a graph There are 2 real roots
x = -1.65 and x = 3.65 to nearest hundredth