The area of a rectangle is:
A = length × width
A rectangular television screen has an area:
A = w² + 2w inches²
width = w
length = A / width = (w² + 2w) / w = w(w + 2) / w = <u>w + 2</u>
Ansver:
<h2><u>
length = w + 2</u></h2><h2><u>
</u></h2><h2><u>
</u></h2>
Answer:
Step-by-step explanation:
Comment
The basic equation of a circle is
(x - a)^2 + (y - b)^2 = r^2
a and b are the coordinates of the center of the circle
r is the radius.
Development of the equation
r = 1 - 1/2 = 1/2. r is the distance between the red dot and the blue dot.
So far what you have is (x - a)^2 + (y - b)^2 = (1/2)^2
The center is the red dot.
x = 1
y = - 1
Answer: (x - 1)^2 + (y + 1/2)^2 = 1/4
Assume that the amount needed from the 5% solution is x and that the amount needed from the 65% solution is y.
We are given that, the final solution should be 42 ml, this means that:
x + y = 42 ...........> equation I
This can also be written as:
x = 42-y .......> equation II
We are also given that the final concentration should be 45%, this means that:
5% x + 65% y = 45% (x+y)
0.05x + 0.65y = 0.45(x+y)
We have x+y = 42 from equation I, therefore:
0.05x + 0.65y = 0.45(42)
0.05x + 0.65y = 18.9 .........> equation III
Substitute with equation II in equation III as follows:
0.05x + 0.65y = 18.9
0.05(42-y) + 0.65y = 18.9
2.1 - 0.05y + 0.65y = 18.9
0.6y = 18.9 - 2.1
0.6y = 16.8
y = 28 ml
Substitute with y in equation II to get x as follows:
x = 42-y
x = 42 - 28
x = 14 ml
Based on the above calculations:
amount of 5% solution = x = 14 ml
amount of 65% solution = y = 28 ml
The correct choice is:
The teacher will need 14 mL of the 5% solution and 28 mL of the 65% solution.
(104+137+154+131+x) / 5 = 130
The calculation part I would like to leave it for you. It's a good practice.
