All categories

3 years ago

Can someone help me w this question? rq?

Mathematics

1 answer:

victus00 [196]3 years ago

5 0

Answer:

Step-by-step explanation:

We can off-the-bat eliminate choices A and B, because the first part of the quadratic formula is a -b. Therefore, the value for b in the quadratic has to be a positive, because the value in the formula is negative. This leaves us with choices C and D. If you look at the discriminant, you will see that our <em>a </em>in the quadratic formula is 3, so your answer choice is C.

You might be interested in

In 2018, the population will grow over 700,000.The population of a city in 2010 was 450,000 and was growing at a rate of 5% per

Firlakuza [10]

Answer:

The year is 2020.

Step-by-step explanation:

Let the number of years passed since 2010 to reach population more than 7000000 be 'x'.

Given:

Initial population is, $P_0=450,000$

Growth rate is, $r=5\%=0.05$

Final population is, $P=700,000$

A population growth is an exponential growth and is modeled by the following function:

$P=P_0(1+r)^x$

Taking log on both sides, we get:

$\log(P)=\log(P_0(1+r)^x)\\\log P=\log P_0+x\log (1+r)\\x\log (1+r)=\log P-\log P_0\\x\log(1+r)=\log(\frac{P}{P_0})\\x=\frac{\log(\frac{P}{P_0})}{\log(1+r)}$

Plug in all the given values and solve for 'x'.

$x=\frac{\log(\frac{700,000}{450,000})}{\log(1+0.05)}\\x=\frac{0.192}{0.021}=9.13\approx 10$

So, for $x > 9.13$ , the population is over 700,000. Therefore, from the tenth year after 2010, the population will be over 700,000.

Therefore, the tenth year after 2010 is 2020.

8 0

3 years ago

Help me plz i dont understand how t=40

timama [110]

Answer:

t=40

Step-by-step explanation:

The sum of all angles in a triangle will always equal 180°. This means that:

(2t-42)+(4t-49)+(2t-49) = 180°

Let's solve this equation!

(2t-42)+(4t-49)+(2t-49) = 180

First we simplify what's on the left side:

2t-42+4t-49+2t-49 = 180

2t+4t+2t-42-49-49 = 180

8t-140 = 180

*Add 140 to both sides

8t = 180+140

8t = 320

Divide both sides by 8 to know what t means:

t = 320/8

t = 40

4 0

3 years ago

The scale of a room in blueprint is 3in 5ft. A wall in the same blueprint is 18in. what are the actual room measurements?

QveST [7]

Answer:

Actual length of wall = 30ft

Step-by-step explanation:

We have scale of a room as 3 inch for 5ft.

We can write scaling factor as:

Scaling factor = 3 /60 (Since 5ft = 60 inches )

Scaling factor = 1/20

Now,

a wall in the blueprint is 18inch.

So actual length of wall can be determined by dividing 18 inch by the scale factor.

i.e actual length of wall = 18 / scale factor = 18 / (1/20)

actual length of wall = 18* 20 = 360 inch = 30ft (Since 360 inch = 30ft)

Hence Actual length of wall = 30ft

5 0

3 years ago

Suppose a city with population 500,000 has been growing at a rate of 7% per year. If this rate continues, find the population

krok68 [10]

Answer:

2,070,281

Step-by-step explanation:

let x = number of years

let y = population

Given:

initial population = 500000
rate of increase = 7%

y = 500000 × 1.07^x

when x = 21:

y = 500000 × 1.07^(21) = 2070281.187... = 2,070,281

5 0

2 years ago

Factor: 24x^3−81<br><br> x^3 is x to the third power

MArishka [77]

Hi again!

24x³ - 81

= 3(2x -3)(4x²+6x+9)

I hope that helps!

Please Brainliest answer :)

8 0

3 years ago