Answer:
[tex]x^2+20x+84=384[/tex]
The dimensions of the painting are 10 in by 18 in
Step-by-step explanation:
The complete question is
A rectangular painting has dimensions x and x + 8. The painting has a frame that is 3 inches wide. The total area of the picture and the frame is 384 inches ^2. Find the dimensions of the painting in inches
we know that
The area of the painting is
[tex]x(x+8)[/tex]
The total area of the picture and the frame is 384 inches ^2
so
[tex](x+3+3)(x+8+3+3)=384[/tex]
[tex](x+6)(x+14)=384[/tex]
[tex]x^2+14x+6x+84=384[/tex]
[tex]x^2+20x+84=384[/tex] ----> correct choice
solve the quadratic equation by graphing
[tex]x^2+20x-300=0[/tex]
using a graphing tool
The solution is x=10 in
see the attached figure
therefore
The dimensions of the painting are 10 in by 18 in