Mathematics, 07.01.2021 15:30 Ully4559

Question 1
Rationalise the denominator.
9
√7-2

Answers: 2

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Answers

Answer from: PastryCrisp

$\displaystyle \frac{9}{\sqrt{7}-2}=3\sqrt{7}+6$

Step-by-step explanation:

Rationalizing the Denominator

Rationalizing the denominator means to get rid of any radicals in the denominator.

We use the conjugate of the denominator to rationalize. The conjugate of a binomial is obtained by changing the sign that is between the two terms while keeping the same order of the terms. For example, the conjugate of

$\sqrt{7}-2$ is $\sqrt{7}+2$ .

We need to use the algebraic identity:

(a-b)(a+b)=a^2-b^2

Let's rationalize

$\displaystyle \frac{9}{\sqrt{7}-2}$

Multiply numerator and denominator by the conjugate of the denominator:

$\displaystyle \frac{9}{\sqrt{7}-2}=\frac{9}{\sqrt{7}-2}\cdot\frac{\sqrt{7}+2}{\sqrt{7}+2}$

Operate in the numerator and apply the identity in the denominator

$\displaystyle \frac{9}{\sqrt{7}-2}=\frac{9(\sqrt{7}+2)}{(\sqrt{7}-2)(\sqrt{7}+2)}$

$\displaystyle \frac{9}{\sqrt{7}-2}=\frac{9\sqrt{7}+18}{(\sqrt{7})^2-2^2}$

$\displaystyle \frac{9}{\sqrt{7}-2}=\frac{9\sqrt{7}+18}{7-4}=\frac{9\sqrt{7}+18}{3}$

Dividing:

$\boxed{\displaystyle \frac{9}{\sqrt{7}-2}=3\sqrt{7}+6}$

Answer from: Quest

step-by-step explanation:

use pothagarean therom

a^2+b^2=c^2 so first ac

acm is a right triangle because c= 90°

and am (the hypotenuse or c) =16+9 =25

but there is not enough info we need another angle or side length

Brainliest and 75 points for whoever can explain how to get these given: △acm, m∠c=90°, cp⊥ am. ap=

Answer from: Quest

when functions are first introduced, you will probably have some simplistic "functions" and relations to deal with, usually being just sets of points. these won't be terribly useful or interesting functions and relations, but your text wants you to get the idea of what the domain and range of a function are. small sets of points are generally the simplest sorts of relations, so your book starts with those.

step-by-step explanation:

state the domain and range of the following relation. is the relation a function?

{(2, –3), (4, 6), (3, –1), (6, 6), (2, 3)}

the above list of points, being a relationship between certain x's and certain y's, is a relation. the domain is all the x-values, and the range is all the y-values. to give the domain and the range, i just list the values without duplication:

domain: {2, 3, 4, 6}

range: {–3, –1, 3, 6}

(it is customary to list these values in numerical order, but it is not required. sets are called "unordered lists", so you can list the numbers in any order you feel like. just don't duplicate: technically, repetitions are okay in sets, but most instructors would count off for this.)

while the given set does indeed represent a relation (because x's and y's are being related to each other), the set they gave me contains two points with the same x-value: (2, –3) and (2, 3). since x = 2 gives me two possible destinations (that is, two possible y-values), then this relation is not a function.

note that all i had to do to check whether the relation was a function was to look for duplicate x-values. if you find any duplicate x-values, then the different y-values mean that you do not have a function. remember: for a relation to be a function, each x-value has to go to one, and only one, y-value.

state the domain and range of the following relation. is the relation a function?

{(–3, 5), (–2, 5), (–1, 5), (0, 5), (1, 5), (2, 5)}

i'll just list the x-values for the domain and the y-values for the range: