Question 1085962
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<pre>
{{{9x^2 + 16x + c}}} = {{{9*(x^2 + (16/9)*x + c/9)}}} = {{{9*(x+8/9)^2}}} + {{{c/9}}} - {{{64/81)}}}  ===>

{{{c/9}}} = {{{64/81}}}  ====>  c = {{{64/9}}}.


<U>Check</U>.  {{{9x^2 + 16x + 64/9}}} = {{{9*(x^2 + (16/9)*x + 64/81)}}} = {{{9*(x+8/9)^2}}} = {{{(3x + 8/3)^2}}}.
</pre>

The solution by "josgarithmetic" is WRONG.



For your safety, ignore it.