960 because 0.8(80%) • 1200 = 960
First you need to distribute the negative to 5,3x and -4 now you have this:
-3.5x+7-5.3x +4 rearrange and combine like terms (matching x's with x's etc.)
-3,5x -5.3x +7+4
-8.8x +11 your final answer there are no more like terms that you can combine.
This is true for any decimals below 1:
If you multiply a number by something greater than 1, it increases
If you multiply a number by 1, it stays the same
If you multiply a number by something less than 1, it decreases
Let x = length and y = width
You would have 2 lengths, so 2x and 3 widths, so 3y
Those need to equal total length of fence:
2x + 3y = 1200
The 3 widths would equal total fence minus the 2 lengths:
3Y = 1200-2x
Solve for y: y = 400 -2/3x
Area = length x width = xy. Replace y :
Area = x(400-2/3x) = 400x-2/3x^2
Differentiate:
400-4x/3 =0
4x/3 = 400
4x = 1200
X = 300
Y = 400-2/3(300) = 200
The dimension would be 300 ft x 200 ft
