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3 years ago

What are the solutions of the quadratic equation 4x^2-8x-12=0

Mathematics

1 answer:

Wewaii [24]3 years ago

6 0

Answer:

Step-by-step explanation:

$4x^2-8x-12=0\\{}\qquad\qquad^{\div4\qquad\div4}\\x^2-2x-3=0\\\\x^2+x-3x-3=0\\\\x(x+1)-3(x+1)=0\\\\(x+1)(x-3)=0\\\\x+1=0\quad\vee\quad x-3=0\\\\x=-1\quad\vee\quad x=3$

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Help?!?!?!!?!?!?! :)

Andru [333]

Answer:

I think its

Step-by-step explanation:

6+2x

3 0

2 years ago

Read 2 more answers

Solve the system using substitution:<br> X+Y=5<br> Y=X - 9

makvit [3.9K]

Answer:

x = 7

y = -2

Step-by-step explanation:

There are 2 equations. The substitution method takes one equation and puts it into the other and solves for 1 variable. Then you take that answer and put into any one equation and solve for the other variable.

Since equation #2 is already given for y = SOMETHING, we take that something and put it into "y" of the 1st equation. Shown below:

$x+y=5\\x+(x-9)=5\\x+x-9=5\\2x=5+9\\2x=14\\x=\frac{14}{2}\\x=7$

We got x = 7

Now, we know from Equation #2, y = x - 9, so

y = x - 9

y = 7 - 9

y = -2

Hence,

y = -2

In coordinate pair, the answer is (7, -2)

3 0

2 years ago

A random sample of math majors taking an introductory statistics course were surveyed after completing the final exam. They were

quester [9]

Answer:

$E(X) =1 *\frac{1}{5} +2 *\frac{2}{5} +7*\frac{2}{5}= 3.8$

Now we can find the second moment with this formula:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i)$

And replacing we got:

$E(X^2) =1^2 *\frac{1}{5} +2^2 *\frac{2}{5} +7^2*\frac{2}{5}= 21.4$

The variance would be given by:

$Var(X) =E(X^2) -[E(X)]^2 = 21.4 -[3.8]^2 = 6.96$

And the deviation would be:

$Sd(X) =\sqrt{6.96}= 2.638$

Step-by-step explanation:

For this case we have the following distribution given:

X 1 2 7

P(X) 1/5 2/5 2/5

We need to begin finding the mean with this formula:

$E(X) = \sum_{i=1}^n X_i P(X_i)$

And replacing we got:

$E(X) =1 *\frac{1}{5} +2 *\frac{2}{5} +7*\frac{2}{5}= 3.8$

Now we can find the second moment with this formula:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i)$

And replacing we got:

$E(X^2) =1^2 *\frac{1}{5} +2^2 *\frac{2}{5} +7^2*\frac{2}{5}= 21.4$

The variance would be given by:

$Var(X) =E(X^2) -[E(X)]^2 = 21.4 -[3.8]^2 = 6.96$

And the deviation would be:

$Sd(X) =\sqrt{6.96}= 2.638$

7 0

3 years ago

HELP FOR BRAINLIEST!!!!!

Hunter-Best [27]

Since rational numbers are any number that can be made into a ratio, i believe all are correct. Normally, they'd be irrational by themselves, but multiplying them by 1/5 changes things.

6 0

3 years ago

1.If a shirt costs 60 dollars, it's marked down to 20% off, what is the amount of the discount?

tresset_1 [31]

Answer:

$12.00

Step-by-step explanation:

20% of $60 is $12.

4 0

2 years ago