Given the area, find the dimension of a rectangle The length of a rectangle is 12m less than three times its width, its area is 63 square meters.

Width   W = 7 m

Length  L =  9 m

Step-by-step explanation:

Area of a rectangle = L * W

Area = 63 m²

L = 3W - 12

Area = L * W

66 = (3W - 12) * W

63 = 3W² - 12W

3W² - 12W - 63 = 0     ( solve W by using quadratic equation)

       -(-12) ± √ -12² - 4 * 3 * (-63)

W =

                      2 * 3

W = 7 ;  W = - 3  

therefore use W = 7 m

solve for L:

L = 3W - 12

L = 3(7) - 12

L =  9 m

check:

Area = L * W

63 =  9 * 7

63 = 63   OK

arrange the equations with like terms in columns.

analyze the coefficients of x or y.

add the equations and solve for the remaining variable.

substitute the value into either equation and solve.

check the solution.

step-by-step explanation: