Answer: 
Step-by-step explanation:
The area of a rectangle can be calculated with this formula:

Where "l" is the length and "w" is the width.
You can identify from the figure that the length and the width of this rectangle are:

Then, you need to substitute this lenght and this width into
:

Now, apply Distributive property:

Finally, you need to add the like terms. Then, you get:

(6x–1)(6x+1) - 4x(9x+2) = −1
Simplify the left side:
36x^2-1 -36x^2-8x = -1
Combine like terms:
-1 -8x = -1
Add 1 to both sides:
-8x = 0
Divide both sides by -8:
x = 0 / -8
x = 0
The root is 0
Answer:
x=25
Explanation:
Using the method of cross multiplication and division set up like so,
(100•4.5)/18 will give you 25.
4.5•100=450
450/18=25
Answer:
A = 38°
Step-by-step explanation:
We are going to use cosine law to find angle A where
a = 4.7
b = 3.9 m
c = 2.9 m

or

cos A = [(4.7)^2 + (3.9)^2 - (2.9)^2]/2(4.7)(3.9)
= 28.89/36.66
= 0.788
A = arccos(0.788) = 38°
Answer:
x=4
y=4√5
Step-by-step explanation:
Set up 3 right triangles and mark their respective angles. The largest will have sides (in typical a,b,c[hypotenuse] order) y, z, and 10. The middle 8, x, and y. The smallest x, 2, and z.
Then since they are all similar triangles, using the midde and smaller triangles, set up the proportionin which both A sides when divided are equal to the B sides.
So 8/x = x/2
Cross multiply and get 16=x^2.
The square root of 16 is 4, so x is 4.
Then using the larger and middle triangles, do the same for the A and C sides.
So y/8 = 10/y.
Cross multiply and get 80=y^2.
Find the square root of it, which since it doesn't have a perfect square, you use a calculator or the whatever theorem and get √4*4*5 or simply 4√5.
So x = 4 and y = 4√5