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2 years ago

EF

Mathematics

1 answer:

BARSIC [14]2 years ago

7 0

Answer:

Step-by-step explanation:

48 + 14 / 2 = 31

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Scientists have discovered a vaccine for a debilitating disease. This year there were 570,000 reported new cases of the disease

Ket [755]

Answer: There are approximately 853827 new cases in 6 years.

Step-by-step explanation:

Since we have given that

Initial population = 570000

Rate at which population decreases is given by

$\frac{2}{3}$

Now,

First year =570000

Second year is given by

$570000\times (\frac{1}{3})$

Third year is given by

$570000(\frac{1}{3})^2$

so, there is common ratio ,

it becomes geometric progression, as there is exponential decline.

so,

$570000,570000\times \frac{1}{3},570000\times( \frac{1}{3})^2,......,570000\times (\frac{1}{3})^6$

a=570000

common ratio is given by

$r=\frac{a_2}{a_1}=\frac{1}{3}$

number of terms = 6

Sum of terms will be given by

$S_n=\frac{a(1-r^n)}{(1-r)}$

We'll put this value in this formula,

$S_6=\frac{570000(1-(\frac{1}{3})^6}{(1-\frac{1}{3})}\\\\=853827.16$

So, there are approximately 853827 new cases in 6 years.

6 0

2 years ago

Help me please on these questions

Fittoniya [83]

The answer to number 23 is D, 49.

8 0

3 years ago

Simplify the following expression by combining like terms and factoring. 2(x-6)+4(2x+1)+3

Shkiper50 [21]

Answer:

5(2x - 1)

Step-by-step explanation:

Given

2(x - 6) + 4(2x + 1) + 3 ← distribute both parenthesis

= 2x - 12 + 8x + 4 + 3 ← collect like terms

= (2x + 8x) + (- 12 + 4 + 3)

= 10x + (- 5)

= 10x - 5 ← factor out 5 from each term

= 5(2x - 1) ← in factored form

4 0

3 years ago

The roots of a quadratic equation ax2+bx+c=0 are 1+i 5 and 1−i 5 . Find possible values of a, b and c.

Anarel [89]

Answer:

Step-by-step explanation:

If the roots are 1 + 5i and 1 - 5i, then you need the factors that result from those roots. They are (x - 1 + 5i) and (x - 1 - 5i). Now what you do with those is FOIL them out. Doing that gives you the following:

$x^2-x+5ix-x+1-5i-5ix+5i-25i^2$ (what a mess, huh?)

The good thing is that several of those terms cancel each other out. +5ix cancels out the -5ix; -5i cancels out the 5i; and the 2 -x terms combine to -2x. That leaves you with:

$x^2-2x-25i^2$

Obviously you're in the section in math that deals with complex (imaginary) numbers so you should know that i-squared is equal to -1. Making that replacement:

$x^2-2x+25$

a = 1, b = -2, c = 25

6 0

3 years ago

Read 2 more answers

Solve (x + 4)2 – 3(x + 4) – 3 = 0 using substitution. u = Select the solution(s) of the original equation.

bezimeni [28]

Answer:

$\dfrac{-5-\sqrt{21}}{2},\ \dfrac{-5+\sqrt{21}}{2}$

Step-by-step explanation:

For the equation $(x+4)^2-3(x+4)-3=0$ use the substitution $u=x+4.$ Then the equation will take look

$u^2-3u-3=0.$

Solve this quadratic equation:

$D=(-3)^2-4\cdot 1\cdot (-3)=9+12=21,\\ \\u_{1,2}=\dfrac{-(-3)\pm \sqrt{21}}{2}=\dfrac{3\pm\sqrt{21}}{2}.$

Thus,

$x+4=\dfrac{3-\sqrt{21}}{2}\text{ or }x+4=\dfrac{3+\sqrt{21}}{2},\\ \\x_1=\dfrac{3-\sqrt{21}}{2}-4=\dfrac{-5-\sqrt{21}}{2}\text{ or }x_2=\dfrac{3+\sqrt{21}}{2}-4=\dfrac{-5+\sqrt{21}}{2}.$

8 0

3 years ago

Read 2 more answers