Calculate the width of the gutter where the depth is 6cms

[Paulo2014]

Homework Statement

The cross-section of a gutter can be represented by the quadratic:
y=4/11x^2-4x+11 where x and y are measurements in cm. Calculate the width of the gutter where the depth is 6cms.

Homework Equations

The Attempt at a Solution

my answer was 1.26cm or 12.6mm but I'm pretty sure that's wrong so could someone please explain how to work it out?

 

[happyg1]

What did you try?

 

[HallsofIvy]

Homework Statement

The cross-section of a gutter can be represented by the quadratic:
y=4/11x^2-4x+11 where x and y are measurements in cm. Calculate the width of the gutter where the depth is 6cms.

It's impossible to say if you won't tells us which of x, y is the width and which is the depth! I might guess that x is twice the width and y the depth, so that you need to solve the equation (4/11)x^2- 4x+ 11= 6. My guess is partly based on the fact that if x is the depth, you would only need to evaluate that (4/11)(6)^2- 4(6)+ 11 and that is too easy!

Homework Equations

The Attempt at a Solution

my answer was 1.26cm or 12.6mm but I'm pretty sure that's wrong so could someone please explain how to work it out?

 

[Paulo2014]

sorry guys... x is width and y is depth