Question

pls tell how to solve !

Answer 1

x = -1/3
p(x) = 27x^3-ax^2-x+3
27 × (-1/3)^3 - a(-1/3)^2 -(-1/3) +3=0
-1-a/9+1/3 +3=0
a/9 = 7/3
a = 7×3 = 21

Answer 2

$given - - > x = - \frac{1}{3} \\ \\ p(x) = 27 {x}^{3} - a {x}^{2} - x + 3$
$p( - \frac{1}{3} ) = 0$
$= > 27( { - \frac{1}{3}) }^{3} - a {( - \frac{1}{3} )}^{2} - ( - \frac{1}{3} ) + 3 = 0 \\ \\ = > - \frac{27}{27} - \frac{a}{9} + \frac{1}{3} + 3 = 0 \\ \\ = > - 1 - \frac{a}{9} + \frac{1}{3} + 3 = 0 \\ \\ = > \frac{18 + 3 - a}{9} = 0 \\ \\ = > 18 + 3 - a = 0 \\ \\ = > a = 21$