An architect is designing square windows with an area of (x^2+20x+100) ft^2. the dimensions of the windows are of the form a x plus b where a and b are whole numbers a. find the dimensions of each square window

The expression that represents the width and length of the square is (x+10).

We factor this expression to find the dimensions.  We want factors of 100 that sum to 20; 10(10) = 100 and 10+10=20.  This gives us

(x+10)(x+10).