SOLUTION: 10. The area of a rectangle is 28 square inches. The length is 8 more than the width. Find the length and the width.

Algebra ->  Rectangles -> SOLUTION: 10. The area of a rectangle is 28 square inches. The length is 8 more than the width. Find the length and the width.      Log On


   

Question 865141: 10. The area of a rectangle is 28 square inches. The length is 8 more than the width. Find the length and the width.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
w width
L length
L=w%2B8
wL=28=w%28w%2B8%29
w%5E2%2B8w-28=0---------Not factorable. Use the general solution to a quadratic equation to find w.

w=%28-8%2Bsqrt%2864%2B4%2A28%29%29%2F2
w=%28-8%2Bsqrt%28176%29%29%2F2
w=%28-8%2Bsqrt%282%2A8%2A11%29%29%2F2
w=%28-8%2B4%2Asqrt%2811%29%29%2F2
highlight%28w=-4%2B2sqrt%2811%29%29-------and use this yourself to find L according to L=w%2B8.