Algebra
posted by Anonymous .
A small painting has an area of 400 cm^2. The length is 4 more than 2 times the width. Find the dimensions of the painting. Solve by completing the square. Round answers to the nearest tenth of a centimeter.

let x = width
2x + 4 = length
A = lw
A = x(2x + 4)
400 = x(2x + 4)
400 = 2x^2 + 4x
200 = x^2 + 2x
x^2 + 2x = 200
do you know how to complete the square? 
Yes, I know how to do it from now. Thank you.

Great!

no i don't understand still
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