Answer: [tex]x^2+16x-612=0[/tex]
Step-by-step explanation:
Let x be the length of the poster.
As per given , width = [tex]\dfrac{x}{2}+8[/tex]
Area = Length x width
i.e.
[tex]306=(\dfrac{x}{2}+8)\times x\\\\\Rightarrow 306=(\dfrac{x+16}{2})\times x\\\\\Rightarrow 306\times2=x^2+16x\\\\\Rightarrow\ x^2+16x-612=0\\\\\Rightarrow\ x=18, x=-34[/tex].
Required equation: [tex]x^2+16x-612=0[/tex]
