applications of rationalexpressions-wordproblem

[momo]

i need help on this question please
7. a poster has 400cm^2 of printed matter. Its margines are 10cm at
the top and bottom, and 5cm at each side

a) suppose the width of the poster is "w" centimeters. Determine
formulas for its length and area

thanks

 

[TchrWill]

i need help on this question please
7. a poster has 400cm^2 of printed matter. Its margines are 10cm at
the top and bottom, and 5cm at each side

a) suppose the width of the poster is "w" centimeters. Determine
formulas for its length and area

Assuming W = total width and L = total length:

1--(W - 10)(L - 20) = 400
2--Simplifying, L = (600 - 20W)/(W - 10)
3--The area is A = W(600 - 20W)/((W - 10)

 

[momo]

thnx man