<u><em>Answer:</em></u>
y = -x² + 60x + 256 in²
<u><em>Explanation:</em></u>
<u>Before we begin, remember the following:</u>
yᵃ × yᵇ = yᵃ⁺ᵇ
<u>Now, for the given problem:</u>
We know that the area of the rectangle is the product of its dimensions (length and width)
<u>This means that:</u>
Area of rectangle = length × width
<u>Now, we are given that:</u>
length of game board = x+4 in
width of game board = -x+64 in
<u>Substitute with the givens in the rule it as follows: </u>
Area of rectangle = length × width
Area of board game = (x+4)(-x+64)
<u>Use the distributive property, compute the product and gather like terms as follows:</u>
Area of board game = (x+4)(-x+64)
Area of board game = x(-x) + x(64) +4(-x) +4(64)
Area of board game = -x² + 64x - 4x + 256
Area of board game = -x² + 60x + 256 in²
Hope this helps :)