Algebra
posted by Anonymous .
The width of a rectangle is three fourths of the length. The perimeter of the rectangle becomes 50 cm when the legth and the width are each increased by two cm. Find the length and the width

Looks like a case for substitution.
width = w
length = l
width = 3/4 length
w = 3/4l
2(w + 2) + 2(l + 2) = 50cm
(2w + 4) + (2l + 4) = 50cm
Substitute w with the information you were given earlier (the width of a rectangle is three fourths the length):
2(3/4l) + 4 + 2l + 4 = 50cm
2(3/4l) + 2l + 8 = 50cm
6/4l + 2l = 42cm
1.5l + 2l = 42cm
3.5l = 42cm
l = 12cm
3/4(12cm) = 9cm
length = 12cm
width = 9cm 
what is the perimeter of the rectangle w/ length x+4/x+3 and width 2x3/x+3