Answer:
The width of the is 4 inches
Explanation:
Assume that the width of the frame is x
∵ The width of the fame is x inches
→ That means each dimension will increase by 2x ⇒ x from each side
∵ The portrait has dimensions of 30“ x 60“
∴ Its dimensions including the frame = (30 + 2x) × (60 + 2x)
∴ The total area of the portrait plus frame = (30 + 2x)(60 + 2x)
→ Multiply the brackets
∵ (30 + 2x)(60 + 2x) = 30(60) + 30(2x) + 2x(60) + (2x)(2x)
∴ (30 + 2x)(60 + 2x) = 1800 + 60x + 120x + 4x²
→ Add the like terms
∴ (30 + 2x)(60 + 2x) = 1800 + 180x + 4x²
∴ The total area of the portrait plus frame = 4x² + 180x + 1800
∵ The total area of the portrait plus frame = 2584 square inches
→ Equate the two right sides of the area
∴ 4x² + 180x + 1800 = 2584
→ Subtract 2584 from both sides
∴ 4x² + 180x + 1800 - 2584 = 0
→ Add the like terms in the left side
∴ 4x² + 180x - 784 = 0
→ Divide all terms by 4 to simplify
∴ x² + 45x - 196 = 0
→ Factorize it to find the value of x
∵ x² + 45x - 196 = (x - 4)(x + 49)
→ Equate the right side by 0
∴ (x - 4)(x + 49) = 0
→ Equate each factor by 0
∵ x - 4 = 0
→ Add 4 to both sides to find x
∴ x = 4
∵ x + 49 = 0
→ Subtract 49 from both sides to find x
∴ x = -49 ⇒ refused it x can not be -ve (no negative dimensions)
∴ The width of the is 4 inches