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3 years ago

Help help math math math math

Mathematics

2 answers:

Kryger [21]3 years ago

7 0

Answer:

C. -3/7

Step-by-step explanation:

Irrational numbers: cannot be written as a fraction

Rational numbers: can be written as a fraction

The only option that contains a fraction, is C

Hope this helps!

Colt1911 [192]3 years ago

5 0

<h3>Answer:</h3>

Option C

<h3>Solution:</h3>

Rational numbers can be expressed as a fraction in the form $\displaystyle\frac{p}{q}$ , where p is the numerator and q is the denominator.
Now, which numbers can and cannot be expressed as a fraction?
First of all, can we express $\sqrt{12}$ as a fraction? No, it's a surd.
Can we express $\pi$ as a fraction? No. Remember, pi is irrational. It has an infinite number of digits after the decimal point (same with √12)
Can we express $-\displaystyle\frac{3}{7}$ as a fraction? Sure. What's more, it's already a fraction.
Can we express √7 as a fraction? No. It's also irrational, like √12 and π.

Hope it helps.

Do comment if you have any query.

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17) Solve the system as matrix equations using inverses. 17) A company produces three models of MP3 players, models A, B, and C.

Vinvika [58]

Answer:

Model A=30, Model B: 20, Model C: 45

Step-by-step explanation:

Let x be the amount of type A mp3 produced, and the amount of model B mp3's produced and z the amount of model C mp3 produced.

Since in total there are 303 hours for electronics work, then:

$3.2x+5.4y+2.2z=303$

Since in total there are 393 hours for assembly, then:

$2.8x+2.4y+5.8z=393$

Since in total there are 416 hours for quality assurance, then:

$4.4x+3.4y+4.8z=416$

Then, the linear system associated to the problem is

$3.2x+5.4y+2.2z=303\\2.8x+2.4y+5.8z=393\\4.4x+3.4y+4.8z=416$

with coefficient matrix $A=\left[\begin{array}{ccc}3.2&5.4&2.2\\2.8&2.4&5.8\\4.4&3.4&4.8\end{array}\right]$ and vector of constant terms $b=\left[\begin{array}{ccc}303\\393\\416\end{array}\right]$

Since the determinant of A is equal to 36.704 then A is invertible.

Then for solve the system $Ax=b$ , is enough find the inverse of A and operate

$Ax=b\\A^{-1}Ax=A^{-1}b\\x=A^{-1}b$

Using Octave we obtain that

$A^{-1}=\left[\begin{array}{ccc}-0.22&-0.50 &0.71\\0.33&0.15&-0.34\\-0.028& 0.35&-0.20\end{array}\right]$

Then

$x=A^{-1}b=\left[\begin{array}{ccc}30\\20\\45\end{array}\right]$

This means that 30 mp3's of model A, 20 of model B and 45 of model C must be produced

8 0

3 years ago

Simplify: (2^2 + 3^4)−^2

Lisa [10]

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