Solve equation by factoring.

Mathematics

1 answer:

3241004551 [841]3 years ago

8 0

Hi ;-)

$x^2+6x-10=30 \ \ /-30\\\\x^2+6x-40=0\\\\a=1, \ b=6, \ c=-40\\\\\Delta=b^2-4ac=6^2-4\cdot1\cdot(-40)=36+160=196\\\\\sqrt{\Delta}=\sqrt{196}=14\\\\x_1=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-6-14}{2}=\boxed{-10}\\\\x_2=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-6+14}{2}=\boxed4$

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solve the problem related to population growth.A city had a population of 23,900 in 2007 and a population of 25,100 in 2012.(a)

Finger [1]

Solution

To find the exponential growth function, we apply the exponential growth formula which is

$N(t)=a(1+k)^t$

Where

$\begin{gathered} a\text{ is the }initial\text{ population} \\ k\text{ is the growth rate} \\ t\text{ is the number of time intervals} \end{gathered}$

Given that

$\begin{gathered} a=23,900 \\ N(5)=25,100 \\ t=2012-2007=5 \end{gathered}$

Substitute the variables into the exponential growth formula

$\begin{gathered} 25100=23900(1+k)^5 \\ \text{Divide both sides by 23,900} \\ \frac{25100}{23900}=\frac{23900(1+k)^5}{23900} \\ 1.05021=(1+k)^5^{} \\ \sqrt[5]{1.05021}=1+k \\ 1.00984=1+k \\ \text{Collect like terms} \\ k=1.00984-1 \\ k=0.00984 \end{gathered}$

Hence, the exponential growth function is

$\begin{gathered} N(t)=23900(1+0.00984)^t_{} \\ N(t)=23900(1.00984)^t \end{gathered}$

Hence, the exponential growth function is

$N(t)=23900(1.00984)^t$

For the population of the city in 2022,

$\begin{gathered} t=2022-2007=15 \\ t=15 \end{gathered}$

Substitute for t into the exponential growth function

$\begin{gathered} N(t)=23900(1.00984)^t \\ N(15)=23900(1.00984)^{15} \\ N(15)=27700\text{ (nearest hundred)} \end{gathered}$

Hence, the population is 2022 is 27700 (nearest hundred)

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1 year ago

estion 6 of 20 : Select the best answer for the question. 6. Gourds at a local farm sell for $.49 per pound. Jim Ring spent $73.

shepuryov [24]

Hey there,

#1 First step.

So we will start off on doing 73.50 ÷ .49 because Jim Ring spent 73.50 and each pound would be $.49 and we need to find out how many pound did he take. So we do 73.50 ÷ .49 and that will give us 150.

Jim Ring took $\boxed{150}$ pounds.

Your correct answer would be A.)

~Jurgen

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4 years ago

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Oksanka [162]

Answer:

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