All categories

2 years ago

0 = -1/14 x^2 + 4x +5 I need to solve for x but I don't get it, PLEASE EXPLAIN AND HELP!!

1 answer:

5 0

Any time you have a fraction within an equation, multiply the entire equation by the denominator to clear the fraction. Since the lead term is negative, we can multiply that away as well
(-14) (0=-1/14x²+4x+5) [now distribute]

0=x²-56x+70 [try to factor into binomials first]
Since 70 only has prime factors of 2·5·7, there is no combination which equals (-56). Use the quadratic formula, or complete the square. I'll use quadratic:

x=-b+/-√(b²-4ac)
2a
a=1, b=(-56), c=70

x= -(-56)+/- √((-56)²-4(1)(70)
2(1)
x= 56+/- √(3136-280)
 2
x=56+/-√(2856)
 2
x=56+/-√(2³·3·119)
 2

x=56+/-2√(714)
 2

x=28+√714; x=28-√714

You might be interested in

50 POINTS! :D

Alexxandr [17]

Answer:

The speed of the first car is 60 mph

Step-by-step explanation:

speed = distance/time

Solve the above equation for distance to get

distance = speed * time

or simply

d = st

Now we use this formula for distance to write an equation for each car.

Let s = speed of second car

Then since the speed of the first car is 10 mph faster, the first car's speed is s + 10.

The time the two cars traveled is equal but unknown, so let the time = t.

First car: speed = s + 10; time = t; distance = 120 miles

d = st

120 = (s + 10)t

(s + 10)t = 120 Equation 1

Second car: speed = s; time = t; 100 miles

d = st

100 = st

st = 100 Equation 2

Equations 1 and 2 form a system of 2 equations in 2 unknowns.

(s + 10)t = 120

st = 100

Distribute t in the first equation.

st + 10t = 120

From the second equation we know st = 100, so substitute 100 for st.

100 + 10t = 120

10t = 120

t = 2

The time traveled was 2 hours.

Equation 2:

st = 100

Substitute t with 2.

s * 2 = 100

s = 50

The speed of the second car was 50 mph.

The speed of the first car is s + 10.

s + 10 = 50 + 10 = 60

Answer: The speed of the first car is 60 mph

8 0

2 years ago

Which graph shows the following system of equations and its solutions? -0.1x-0.3y=1.2 and 0.2x-0.5y=2

Vera_Pavlovna [14]

Answer:

Option b is the correct answer as both the equations are true for given solution.

Step-by-step explanation:

Given equations are:

-0.1x-0.3y=1.2

0.2x-0.5y=2

We can observe each graph and find the point that is the solution and put the point in the equations to know if that point is the solution

For option A:

(0,4)

Putting x=0 and y = 4 in both equations

$-0.1(0)-0.3(4)=1.2\\0-1.2 =1.2\\-1.2 \neq 1.2\\0.2(0)-0.5(4)=2\\0-2 = 2\\-2 \neq 2$

This is not the correct answer as both equations are not true with this solution

For Option B:

(0,-4)

Putting x = 0 and y = -4 in both equations

$-0.1(0)-0.3(-4)=1.2\\0+1.2 = 1.2\\1.2 = 1.2\\0.2x-0.5y=2\\0.2(0)-0.5(-4) = 2\\2 = 2$

Both equations are true for (0,-4) hence it is the solution of the system.

For Option C:

(4,0)

$-0.1(4)-0.3(0)=1.2\\-0.4-0 = 1.2\\-0.4 \neq 1.2\\0.2x-0.5y=2\\0.2(4)-0.5(0) = 2\\0.8 \neq 2$

Not true for both equations

Hence,

Option b is the correct answer.

7 0

2 years ago

Alguien me ayuda pls

Romashka [77]

Answer:

good

Step-by-step explanation:

6 0

2 years ago

In 2015, there were roughly 1x10^6 high school football players and 2x10^3 professional football players in the United States.

melisa1 [442]

Answer:

500.

Step-by-step explanation:

(1 * 10^6) / (2 * 10^3)

= 1/2 * 10^6/10^3

= 0.5 * 10^3

= 5 * 10^2

= 500.

5 0

2 years ago

Write as a mathematical expression he product of 5 and x

Vaselesa [24]

The answer to the question

8 0

2 years ago