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3 years ago

0=x^2+4x+1. Khan academy

1 answer:

34kurt3 years ago

4 0

Now, to find 'x' you will apply the Null Factor Law. This means you will now let 'x' = 0, and simply move the -2 over to the other side to find your answer. Note: since we are using a perfect square, x will only have one value since there is only one answer (x-2) in the brackets, meaning in this case we can ignore the exponent (as the answers will be the same). If there was more than one answer in the bracket (e.g. (x-4) and (x-6)), then we would apply Null Factor Law to both brackets and solve for x.

(x−2)=5

x=5+2

x=7

You might be interested in

Use the distributive property to simplify 3 + 5c(2 + 6c) completely.

Charra [1.4K]

Answer:

Distributive property says that:

(A + B)*C = A*C + B*C

Now let's try to use it in our expression:

3 + 5*c*(2 + 6*c)

Here we can take the two terms inside the parentheses as A and B, and the term that multiplies them as C, then distributing we get:

3 + (5*c)*2 + (5*c)*(6*c)

Now remember that the multiplications are associative and commutative, then we can write this as:

3 + (2*5)*c + (5*6)*(c*c)

3 + 10*c + 30*c^2

And we can't simplify it anymore.

7 0

2 years ago

An object is dropped from a height of 1700 ft above the ground. The function h=-16t^2+1700 gives the object’s height h in feet d

Softa [21]

The answer is
a) 1000=-16t^2+1700, implies t² = -700 /-16, and t= 6.61s
b) 970= -16t^2+1700, implies t² = -730 /-16, and t=6.75s

c)
reasonable domain of h
h is polynomial function, so its domain is R, (all real number)
its range
the inverse of h is h^-1 = sqrt (1700- t / 16), and its domain is 
1700- t / 16>=0, so t <1700,
the range of h is I= ]-infinity, 1700]

8 0

3 years ago

I need help with this problem

castortr0y [4]

Answer:

c. 106 million

Step-by-step explanation:

A = number of people in the sample that use public transportation 5 or more days per week

A = 2,067,153

B = number of people total in the sample

B = 4,295,280

C = proportion of those in the sample that use public transportation 5 or more days per week

C = A/B

C = (2,067,153)/(4,295,280)

C = 0.48126 approximately

Multiply this value by the figure 220 million to compute the estimated number of people who use public transportation 5 or more days per week

C*(220 million) = 0.48126*(220 million) = (0.48126*220) million = 105.8772 million = 106 million

6 0

3 years ago

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

AysviL [449]

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.

4 0

3 years ago

Will a 9/32 inch diameter pin fit into a reamed hole with a diameter of 0.278 inch? (Do not round off your answer and express it

ollegr [7]

Answer:

9/32 inch diameter pin will not fit into a reamed hole with a diameter of 0.278 inch

Step-by-step explanation:

Diameter of reamed hole = 0.278 inch

Radius of reamed hole = $\frac{0.278}{2} =0.139$

Surface area of reamed hole = $\pi r^2$

Surface area of reamed hole = $3.14 \times (0.139)^2$

Surface area of reamed hole = 0.06066794

Diameter of pin = $\frac{9}{32}$

Radius of pin = $\frac{9}{64}$

Surface area of pin = $\pi r^2 = 3.14 \times ( \frac{9}{64})^2=0.0620$

Since the surface area of pin is more than the surface area of hole .

So, a 9/32 inch diameter pin will not fit into a reamed hole with a diameter of 0.278 inch

7 0

3 years ago