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AfilCa [17]
3 years ago
8

Evaluate the expression 3x + 21 for x=3

Mathematics
1 answer:
hichkok12 [17]3 years ago
6 0

Answer:

30

Step-by-step explanation:

Problem = 3x + 21 for x=3

3(3) +21 --- subsitute the three for the x

9 + 21 ---- multiply the 3s together

30 ----- add

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Which polynomial function could be represented by the graph below?
Zinaida [17]

Answer:

third answer

Step-by-step explanation:

The end behavior of the function indicates that the leading coefficient of x is negative (as x approaches infinity, f(x) approaches negative infinity for cubic functions with negative leading coefficients). This eliminates the first 2 answers. Next, factor out the common factor from the 3rd answer and set it to 0 to see if the roots of the polynomial shown on the graph (x=-3, x=2) match that of the answer.

  • factor out -2x since each term in the 3rd answer is divisible by -2x => -2x(x^2+x-6)
  • set the factored polynomial equal to 0 => -2x(x^2+x-6)
  • divide both sides by -2x => 0 = x^2+x-6
  • factor => (x+3)(x-2) = 0
  • find zeros by setting both factors equal to 0 => x=-3, x=2

This means that the 3rd answer is correct. The last answer, while having the correct leading coefficient, will produce roots of 3 and -2 instead of -3 and 2, which is shown on the graph.

6 0
3 years ago
A cylindrical 2014-t6 aluminum alloy bar is subjected to compression-tension stress cycling along its axis; results of these tes
Pani-rosa [81]

Complete part of Question:

Assume a factor of safety of 3.0

The Maximum stress versus logarithm of the number of cycles to fatigue failure curve for 2014-T6 Aluminium bar is attached to this solution

Answer:

The maximum allowable load amplitude is 6403.33 N

Step-by-step explanation:

diameter of the bar, d = 12 mm

d = 0.012 m

Cross sectional area of the bar, A = πd²/4

A = π*0.012²/4

A = 0.000113 m²

From the Maximum stress versus logarithm of the number of cycles to fatigue failure for 2014-T6 Aluminium bar attached to this solution;

At 10⁷ cycles, Maximum stress, S = 170 MPa

S = 170 * 10⁶ Pa

Factor of safety, N = 3.0

The tensile stress is given by the formula:

\sigma = S/N\\\sigma = \frac{170 * 10^{6} }{3} \\\sigma = 56.67 * 10^{6} N/m^{2}

The tensile stress is also given by:

\sigma = F/A\\\sigma = F/0.000113

F/0.000113 = 56.67 * 10⁶

F = 56.67 * 10⁶ * 0.000113

F = 6403.33 N

The maximum allowable load amplitude is 6403.33 N

3 0
3 years ago
Read 2 more answers
Enlarge the rectangle.
liq [111]

Answer:

1: greater than 1

2:between 0 and 1

Step-by-step explanation:

3 0
3 years ago
Read 2 more answers
Aubreys dinner cost $85 she tips the waitstaff 30% for excellent service
Pavel [41]

Answer:

25.5

Step-by-step explanation:

4 0
3 years ago
In 8 years, a girl will be 3 years older than twice her present age. How old is she now<br>​
Lisa [10]

Answer:

5

Step-by-step explanation:

You can express this as a system of equations:

x in this instance will be her present age.

x + 8 = 2x + 3

simply solve for x after this by subtracting three and x from both sides, and you’ll find that x is 5.

5 0
4 years ago
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