Guy wants to swim 500 meters. After 75 meters, he takes a break. What percent of his goal has he already met?

Two sets of equatic expressions are shown below in various forms: Line 1: x2 + 3x + 2 (x + 1)(x + 2) (x + 1.5)2 − 0.25 Line 2: x

kherson [118]

Answer: The correct line is

$\textup{Line 1 :}x^2+3x+2=(x+1)(x+2)=(x+1.5)^2-0.25.$

Step-by-step explanation: We are given the following two sets of quadratic expressions in various forms:

$\textup{Line 1: }x^2+3x+2=(x+1)(x+2)=(x+1.5)^2-0.25,\\\\\textup{Line 2 :}x^2+5x+6=(x+2)(x+3)=(x+2.5)^2+6.25.$

We are to select one of the lines from above that represent three equivalent expressions.

We can see that there are three different forms of a quadratic expression in each of the lines:

First one is the simplified form, second is the factorised form and third one is the vertex form.

So, to check which line is correct, we need to calculate the factorised form and the vertex form from the simplified form.

We have

$\textup{Line 1: }\\\\x^2+3x+2\\\\=x^2+2x+x+2\\\\=x(x+2)+1(x+2)\\\\=(x+1)(x+2),$

and

$x^2+3x+2\\\\=x^2+2\times x\times 1.5+(1.5)^2-(1.5)^2+2\\\\=(x+1.5)^2-2.25+2\\\\=(x+1.5)^2-0.25.$

So,

$\textup{Line 1 :}x^2+3x+2=(x+1)(x+2)=(x+1.5)^2-0.25.$

Thus, Line 1 contains three equivalent expressions.

Now,

$\textup{Line 2: }\\\\x^2+5x+6\\\\=x^2+3x+2x+6\\\\=x(x+3)+2(x+3)\\\\=(x+2)(x+3),$

and

$x^2+5x+6\\\\=x^2+2\times x\times 2.5+(2.5)^2-(2.5)^2+6\\\\=(x+2.5)^2-6.25+6\\\\=(x+2.5)^2-0.25\neq (x+2.5)^2+6.25.$

So,

$\textup{Line 2 :}x^2+3x+2=(x+1)(x+2)=(x+1.5)^2+6.25.$

Thus, Line 2 does not contain three equivalent expressions.

Hence, Line 1 is correct.

7 0

3 years ago

Use any method to estimate how much Joan earns in all working 6.75 hours for 2 days earning $15.70 per hour.show your work

alexdok [17]

Answer:

$ 211.95

Step-by-step explanation:

soooo your supposed to multiply 6.75hr and 15.70

and get 105.975

the multiply that by 2

answer: $211.95

8 0

2 years ago

In an insect colony there are 270 insects after 9 days. If there were initially 80 insects how long will it take the population

Semenov [28]

Answer:

The time it will take the population to grow to 800 insects is 17 days.

Step-by-step explanation:

The growth function of the insects is exponential.

The exponential growth function is:

$y=a(1+r)^{t}$

Here,

y = final value

a = initial value

r = growth rate

t = time taken

It is provided that there were 270 insects after 9 days and initially there were 80 insects.

Compute the value of r as follows:

$y=a(1+r)^{t}\\\\270=80(1+r)^{9}\\\\3.375=(1+r)^{9}\\\\\ln(3.375)=9\cdot \ln(1+r)\\\\0.135155=\ln(1+r)\\\\1+r=1.14471\\\\r=0.145$

Now, compute the time it will take the population to grow to 800 insects as follows:

$800=80(1+0.145)^{t}\\\\10=(1.145)^{t}\\\\\ln(10)=t\cdot \ln(1.145)\\\\t=17.00522\\\\t\approx 17$

Thus, the time it will take the population to grow to 800 insects is 17 days.

7 0

3 years ago

1. Which equation can you use to find the value of x?

Alika [10]

Answer:

It's a proportion.

2 is to x as 15 is to 9, or 2/x = 15/9.

Multiply the means and extremes

15x = 18

divide both sides by 15 to get x by itself.

x = 1.2

Step-by-step explanation:

6 0

2 years ago

5 x + 5 = -5 what is x?

romanna [79]

Answer:

x=-2

Step-by-step explanation:

6 0

2 years ago