#### Answer

x=4

#### Work Step by Step

A(-2,3) B(x,6) C(8,8)
Using Slope formula
$m_{AB}$= $\frac{y2-y1}{x2-x1}$ = $\frac{6-3}{x+2}$
$m_{BC}$= $\frac{y2-y1}{x2-x1}$ = $\frac{8-6}{8-x}$
Given that pointrs are collinear, so
$m_{AB}$ = $m_{BC}$
$\frac{6-3}{x+2}$ = $\frac{8-6}{8-x}$
3(8-x) = 2(x+2)
24 - 3x = 2x +4
5x=20
x=4