SOLUTION: I don't understand this problem can someone please help me. The area of a rectangle is 45 square cm. If the length is 4 cm greater than the width, what are the dimensions of the r

Algebra ->  Expressions-with-variables -> SOLUTION: I don't understand this problem can someone please help me. The area of a rectangle is 45 square cm. If the length is 4 cm greater than the width, what are the dimensions of the r      Log On


   

Question 128995: I don't understand this problem can someone please help me. The area of a rectangle is 45 square cm. If the length is 4 cm greater than the width, what are the dimensions of the rectangle?.
Answer by oscargut(2103) About Me  (Show Source):
You can put this solution on YOUR website!
you have to find the length and the width of the rectangle
let denotate L=length and W=width
L=W+4

area = L*W =45 then (W+4)W=45 then W^2+4W-45=0
then W+=+%28-4+%2B-+sqrt%28+%284%29%5E2-4%2A1%2A-45+%29%29%2F%282%2A1%29+
= +%28-4+%2B-+sqrt%28196%29%29%2F%282%2A1%29+
=+%28-4+%2B-+14%29%2F2+
=+%28-2+%2B-+7%29+
solutions are W=-9 and W=5 then W=5
then W=5 and L=9