The length of a rectangle is 4 inches more than three times the width. The perimeter is 80 inches. Find the length and width. Someone help please

The length is 31 inches and the width is 9 inches

Step-by-step explanation: The first clue we have is that the length is given as 4 inches more than three times the width. So if the width is W, then the length would be three times W and then add four to it. Hence, the length would be,

3W + 4

Therefore Length = 3W + 4 and Width = W

If the perimeter has been given as 80 inches, we can now apply the formulae for perimeter of a rectangle.

Perimeter = 2(L + W)

(Having determined the values of Length and Width...)

Perimeter = 2(3W + 4 + W)

Perimeter = 2(4W + 4)

Perimeter = 8W + 8

Having been given the perimeter as 80,

80 = 8W + 8

Subtract 8 from both sides of the equation

72 = 8W

Divide both sides of the equation by 8

9 = W

Having calculated the width as 9 inches, the length given as 3W + 4 now becomes

L = 3(9) + 4

L = 27 + 4

L = 31

Therefore length = 31 inches and width = 9 inches

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,