The area of a rectangle wall of a barn is 320 square feet. it's length is12 feet longer than twice it's width. find the length and width of the wall of the barn.

Length = 32 feet

Width = 10 feet

Step-by-step explanation:

The area of a rectangle = length (L) x width (W)

The relationship between the length and width is that

L = 12 + 2W (i)

therefore

Area = L x W can be rewritten as (12 + 2W) x W

320 =  (12 + 2W) x W

320 = 12W + 2W^2

this can then be turned into a quadratic equation:

2W^2 + 12W - 320 = 0

Divide through by 2

W^2 + 6W - 160 = 0

W^2 - 10W + 16W - 160 = 0

W(W- 10) + 16(W- 10) = 0

(W- 10)(W + 16) = 0

hence W = -16 and 10

since width cannot be a negative value,

Width = 10

hence substituting for width = 10 into equation (i)

L = 12 + 2(10)

L = 12 +20 = 32

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3

answer: the answer is 110