SOLUTION: a framed picture has lenght 35 cm and width 25 cm. the picture itself has area 375 cm. how far is it from the edge of the picture of the frame if its distance is uniform around the

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: a framed picture has lenght 35 cm and width 25 cm. the picture itself has area 375 cm. how far is it from the edge of the picture of the frame if its distance is uniform around the      Log On


   



Question 901966: a framed picture has lenght 35 cm and width 25 cm. the picture itself has area 375 cm. how far is it from the edge of the picture of the frame if its distance is uniform around the picture
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
a framed picture has lenght 35 cm and width 25 cm. the picture itself has area 375 cm. how far is it from the edge of the picture of the frame if its distance is uniform around the picture
.
Let x = width (cm) of frame
then
(35-2x)(25-2x) =375
875 - 70x - 50x + 4x^2 = 375
875 - 120x + 4x^2 = 375
4x^2 - 120x + 875 = 375
4x^2 - 120x + 575 = 0
.
applying the quadratic formula we get:
x = {24, 6}
throw out the 24 (extraneous) leaving
x = 6 cm
.
Details of quadratic follows:
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 4x%5E2%2B-120x%2B575+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-120%29%5E2-4%2A4%2A575=5200.

Discriminant d=5200 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--120%2B-sqrt%28+5200+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-120%29%2Bsqrt%28+5200+%29%29%2F2%5C4+=+24.01387818866
x%5B2%5D+=+%28-%28-120%29-sqrt%28+5200+%29%29%2F2%5C4+=+5.98612181134003

Quadratic expression 4x%5E2%2B-120x%2B575 can be factored:
4x%5E2%2B-120x%2B575+=+4%28x-24.01387818866%29%2A%28x-5.98612181134003%29
Again, the answer is: 24.01387818866, 5.98612181134003. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+4%2Ax%5E2%2B-120%2Ax%2B575+%29