Remark
It's a right triangle so the Pythagorean Theorem applies. All you have to do is put the right things in the right places of the formula.
Givens
a = x
b = x + 4
c = 20
Formula and Substitution.
a^2 + b^2 = c^2
x^2 + (x + 4)^2 = 20^2
Solution
x^2 + x^2 + 8x + 16 = 20 Collect the like terms on the left.
2x^2 + 8x + 16 = 20 Subtract 20 from both sides.
2x^2 + 8x + 16 - 20 = 0
2x^2 + 8x - 4 = 0 Divide through by 2
x^2 + 4x - 2 = 0
Use the quadratic formula
a = 1
b = 4
c = - 2

From which x = (-4 +/- sqrt(24) ) / 2
x1 = (- 4 +/- sqrt(4*6) ) / 2
x1 = (- 4 +/- 2 sqrt(6) ) / 2
x1 = -2 + sqrt(6)
x2 = -2 - sqrt(6) This is an extraneous root. No line can be minus.
x1 = + 0.4495
x2 = x + 4 = 4.4495
Answer:
A.58.81
Step-by-step explanation:
x = number of parties attended
y = number of text messages sent
The residual is the difference between the actual number of text messages sent (200) and the number of texts predicted by the regression model:

The residual is:

The answer is alternative A.58.81
Step 2 is wrong: 4x - x = 5x
X = -11 is the actual answer, pretty sure.
Hope this helps and please mark as brainliest. If you have any other doubts, feel free to ask.
( 1, ∞) is the domain of (b o a)(x)
<h3>
What is Function?</h3>
A function is defined as a relation between a set of inputs having one output each.
According to the question,

To find the domain of the composite function,

Therefore,

Hence , [ 1, ∞ ] is is the domain of (b o a)(x).
learn more about function here:brainly.com/question/12431044
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We will see that the price of the bike helmet without the tax is $50
<h3>
How to find the original price?</h3>
Let's define P as the original price, this is the 100%.
We know that a tax rate of the 9% is equal to $4.50, then we can write two equations:
100% = P
9% = $4.50
We can take the quotient between these two equations and solve that for P, we will get:
(100%/9%)*$4.50 = P = $50
So the price of the helmet, without tax, is $50.
If you want to learn more about taxes, you can read:
brainly.com/question/14345924