L = w - 20
12000 = w × ( w - 20 )
12000 = w^2 - 20w
w^2 - 20w - 12000 = 0
( w - 10 ) ( w - 10 ) = 0
width = 10
i am a mathematics teacher. if anything to ask please pm me
You can do all strategies. Multiplication, Division, Addition, and Subtraction are the strategies because you can multiply 7 by 4 to get 28, divide 56 by 2 to get 28, add 14 by 14 to get 28, or subtract 40 by 12 to get 28.