SOLUTION: perimeter of a rectangle is 42 in. the area is 98sq in. what are the dimensions of the rectangle?

Algebra ->  Surface-area -> SOLUTION: perimeter of a rectangle is 42 in. the area is 98sq in. what are the dimensions of the rectangle?      Log On


   

Question 977698: perimeter of a rectangle is 42 in. the area is 98sq in. what are the dimensions of the rectangle?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Better to study and use the lesson. You can still go this way:

x and y, the dimensions.
system%282x%2B2y=42%2Cxy=98%29

system%28x%2By=21%2Cxy=98%29

y=21-x
-
x%2821-x%29=98
21x-x%5E2=98
-x%5E2%2B21x-98=0
highlight_green%28x%5E2-21x%2B98=0%29


98=2*7*7, probably the quadratic not factorable?

Discriminant: 21%5E2-4%2A98=49=7%5E2
x=%2821%2B-+7%29%2F2
highlight%28x=7%29 or highlight%28x=14%29

The rectangle's dimensions will be 7 and 14.