The length of a rectangle is 3 cm less than twice the width. If the perimeter is 42 cm, what is the length of the rectangle?
1 answer:
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Answer:
Solution : (15, - 11)
Step-by-step explanation:
We want to solve this problem using a matrix, so it would be wise to apply Gaussian elimination. Doing so we can start by writing out the matrix of the coefficients, and the solutions ( - 5 and - 2 ) --- ( 1 )
Now let's begin by canceling the leading coefficient in each row, reaching row echelon form, as we desire --- ( 2 )
Row Echelon Form :
Step # 1 : Swap the first and second matrix rows,
Step # 2 : Cancel leading coefficient in row 2 through ,
Now we can continue canceling the leading coefficient in each row, and finally reach the following matrix.
As you can see our solution is x = 15, y = - 11 or (15, - 11).
To solve this we are going to use the formula for the volume of a sphere: 
where
is the radius of the sphere
Remember that the radius of a sphere is half its diameter; since the first radius of our sphere is 24 cm,
. Lets replace that in our formula:
Now, the second diameter of our sphere is 36, so its radius will be:
. Lets replace that value in our formula one more time:
To find the volume of the additional helium, we are going to subtract the volumes:
Volume of helium=
We can conclude that the volume of additional helium in the balloon is approximately <span>17,194 cm³.</span>
where
Remember that the radius of a sphere is half its diameter; since the first radius of our sphere is 24 cm,
Now, the second diameter of our sphere is 36, so its radius will be:
To find the volume of the additional helium, we are going to subtract the volumes:
Volume of helium=
We can conclude that the volume of additional helium in the balloon is approximately <span>17,194 cm³.</span>