Respuesta :
The area of the PICTURE is, indeed, 20 x 30 = 600 square inches. But the frame surrounds the picture, and the width of the strips making up the frame is x (see diagram).
The width of the picture frame is 20 + 2x (the width of the picture plus two strips of frame).
The length of the picture frame is 30 + 2x (the length of the picture plus two strips of frame.
The area of the frame is (20 + 2x)(30 + 3x). To get the area of JUST the frame, subtract out the area of the picture. You get (20 + 2x)(30 + 2x) - 600.
This isn't really an equation; it's an expression, and it could be written in a different form by multiplying the two binomials out and simplifying.
I have assumed that the 20 in and 30 in measurements give the size of the picture INSIDE the frame!
The width of the picture frame is 20 + 2x (the width of the picture plus two strips of frame).
The length of the picture frame is 30 + 2x (the length of the picture plus two strips of frame.
The area of the frame is (20 + 2x)(30 + 3x). To get the area of JUST the frame, subtract out the area of the picture. You get (20 + 2x)(30 + 2x) - 600.
This isn't really an equation; it's an expression, and it could be written in a different form by multiplying the two binomials out and simplifying.
I have assumed that the 20 in and 30 in measurements give the size of the picture INSIDE the frame!
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