When you have an equation that has variables and you know the value of those variables, just plug it it. So plugging the vaules we get Just evaluating we get 4
To evaluate a function with certain defined values, we must <em>substitute</em> the values in the equation, perform the indicated operations and in this way we obtain the final value.
Area of wall = 9 * 12 = 108 ft^2 Width of TV = x Lenght = 2x Diagonal of TV = 72 " = 6 ft
x^2+(2x)^2=6^2 x^2+4x^2=36 5x^2=35 x^2=36/5 x=sqrt(36/5) Width = 2.68 ft. Length = 2.68 * 5.36 = 14.36 ft^2 Area of wall - area of tv = 108 - 14.36 = 93.64 ft