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3 years ago

Which quadratic equation has roots –2 and 1/5?

Mathematics

1 answer:

AysviL [449]3 years ago

4 0

Answer:

The equation $5x^2\:+\:9x\:-\:2\:=\:0$ has roots –2 and 1/5.

Hence, the option 'a' is the correct answer.

Step-by-step explanation:

Checking the equation

$5x^2\:+\:9x\:-\:2\:=\:0$

putting x = -2 in the equation

$5\left(-2\right)^2\:+\:9\left(-2\right)-\:2\:=\:0\:$

$2^2\cdot \:\:5-9\cdot \:\:2-2=0$

$2^2\cdot \:5-18-2=0$

$20-20=0$

$0=0$

L.H.S=R.H.S

putting x = 1/5 in the equation

$5\left(\frac{1}{5}\right)^2\:+\:9\left(\frac{1}{5}\right)-\:2\:=\:0\:$

$5\left(\frac{1}{5}\right)^2+9\cdot \:\frac{1}{5}-2=0$

$\frac{1}{5}+\frac{9}{5}-2=0$

$2-2=0$

$0=0$

L.H.S=R.H.S

As putting x = -2 and x = 1/5 satisfy the equation.

Therefore, the equation $5x^2\:+\:9x\:-\:2\:=\:0$ has roots –2 and 1/5.

Hence, the option 'a' is the correct answer.

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Algebra help

Vilka [71]

To determine the correct ordered pairs which will agree with the function, we can substitute values to the function and see whether it agree with each other. We do as follows:

(0,1)
 f(x)=128(0.5)^0
 f(x)=128

(1,64)
 f(x)=128(0.5)^1
f(x) = 64 <--------CORRECT ANSWER

(3,16)
 f(x)=128(0.5)^3
f(x) = 16 <--------CORRECT ANSWER

(8,0.5)
 f(x)=128(0.5)^8
f(x) = 1/2

Hope this answers the question. Have a nice day.

5 0

3 years ago

What is the Value of X please help!

Brums [2.3K]

Answer:

x = 7cm

Step-by-step explanation:

$\frac{36}{6} = \frac{42}{x}\\\\6 = \frac{42}{x}\\\\x = \frac{42}{6} = 7$

4 0

3 years ago

Which of the following is the solution set to the inequality −25x+14>20?

Bezzdna [24]

Answer:

Option C. $x < -15$

Step-by-step explanation:

The correct inequality is

$-\frac{2}{5}x+14 >20$

Solve for x

subtract 14 both sides

$-\frac{2}{5}x+14-14 >20-14$

$-\frac{2}{5}x >6$

Multiply by -1 both sides

$\frac{2}{5}x < -6$

Multiply by 5/2 both sides

$x < -6(\frac{5}{2})$

$x < -15$

8 0

3 years ago

What is the value of the rate of change when we put a glass of water at room temperature in the freezer for 15 minutes, what is

alexgriva [62]

Answer:

Step-by-step explanation:

I do not understand your question very well but I think that the state of the glass of the water would be liquid and solid at the same time since the water would not freeze 100% and would be with small pieces of solid and some parts liquid, in terms of temperature, I think that at 5 minutes it would be 5 ° C and at 10 it would be 3-4 ° C the longer it is in the freezer the less its temperature will be

(All of that is my point of view)

Average temperature 30 °

So :

30 ÷ 15 = 2 °

30 ÷ 10 = 3 °

30 ÷ 5 = 6 °

3 0

3 years ago

Giovanni and Jean started a 120-mile bicycle race at the same time. Giovanni cycled at 23.9 miles per hour while Jean cycled at

ehidna [41]

Answer:

Giovanni was 0.5 miles from the finish line

Step-by-step explanation:

This is a problem of movement with constant velocity.

For this kind of problems, generally it is enough to remember the definition of average velocity v:

$v=\frac{x}{t}$

Where x is the change in position that took place in an interval t.

First, find the time that Jean, who cycled at 24 miles per hour, spent on the race:

Isolating t from the last equation,

$t=\frac{x}{v}$ , and replacing the data for Jean movement:

$t=\frac{120}{24}=5h$

Second, find what was the distance that Giovanni had cycled when Jean crossed the line:

$x=v*t\\ x=23.9*5=119.5$

When Jean crossed the line he had cycled 120 miles, and Giovanni 119.5; so Giovanni was 0.5 miles from the finish line.

4 0

3 years ago