+64 You hang nine identical square picture frames on a wall.
a. Write a polynomial that represents the area of the picture frames, not including the pictures.
b. The area in part (a) is 81 square inches. What is the side length of one of the picture frames? Explain your reasoning.
Its the last question on the homework, and I woke up 2 hours ago just to get this finished.
+26387 You hang nine identical square picture frames on a wall.
a. Write a polynomial that represents the area of the picture frames, not including the pictures.
\(\begin{array}{rcll} A = 9\cdot (x^2-4^2) \\ \end{array} \)
b. The area in part (a) is 81 square inches. What is the side length of one of the picture frames? Explain your reasoning.
\(\begin{array}{rcll} A &=& 9\cdot (x^2-4^2) \\ 81 &=& 9\cdot (x^2-4^2) \\ 81 &=& 9\cdot (x^2-16) \\ 9\cdot (x^2-16) &=& 81 \qquad | \qquad : 9 \\ x^2-16&=& 9 \qquad | \qquad +16 \\ x^2 &=& 25 \qquad | \qquad \sqrt{} \\ x &=& 5\ in. \\ \end{array}\)
