\ if twice a number added to 3 is divided by the number plus 7 , the result is five thirds. find the number.

PC-CSIL

pav-90 [236]

The equality used is Subtraction property of equality

Option A is correct

Step-by-step explanation:

We need to identify which option best explains or justifies Step 1.

Step 1 is: $-c = ax^2 + bx$

The given equation is: $0 = ax^2 + bx + c$

To get the equation for step 1 we need to subtract c on both sides of equation i.e using subtraction property of equality

$0-c = ax^2 + bx + c-c$

$-c = ax^2 + bx$

So, The equality used is Subtraction property of equality

Option A is correct.

Keywords: Solving Quadratic Equations

Learn more about Solving Quadratic Equations at:

#learnwithBrainly

5 0

3 years ago

Which of the following is a solution of the system 2x + y = 9 and 3x + 5y = 19.

Nezavi [6.7K]

2x+y=9

3x+5y=19

I will do this problem in 2 ways. I.)Substitution II.)Elimination

Solution I.) Substitution

We can subtract 2x from both sides in the first equation.

y=9-2x

Now we can substitute the y in the second equation with 9-2x

3x+5(9-2x)=19

-7x+45=19

-7x=-26

x=26/7

y=9-2(26/7)=11/7

Solution II.)Elimination

We can multiply both side of first equation by 5 to get a 5y in both equations.

10x+5y=45

Now because both are positive 5y we just need to do simple subtraction of the 2 equation, each side respectively.

(10x+5y)-(3x+5y)=45-19

7x=26

x=26/7

2*26/7+y=9

y=11/7

Ultimately you get the same answer, both are viable methods, some problems are faster with one method but I recommend mastering both since they are very useful.

4 0

2 years ago

What is the answer (X^2)(X)(4)

enot [183]

Answer:

Simplified: 4X^3

Step-by-step explanation:

Simplify the expression.

3 0

2 years ago

5/6 x 12 in simplest form?

Jlenok [28]

Answer:

10

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Suppose that a college determines the following distribution for X = number of courses taken by a full-time student this semeste

lidiya [134]

Answer:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 3*0.07 +4*0.4 +5*0.25 +6*0.28= 4.74$ In order to find the variance we need to calculate first the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 3^2*0.07 +4^2*0.4 +5^2*0.25 +6^2*0.28= 23.36$ And the variance is given by:

$Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924$

And the deviation would be:

$Sd(X) =\sqrt{0.8924} =0.9447$

Step-by-step explanation:

Previous concepts

The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.

The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).

Solution to the problem

For this case we have the following distribution given:

X 3 4 5 6

P(X) 0.07 0.4 0.25 0.28

We can calculate the mean with the following formula:

$E(X) = \sum_{i=1}^n X_i P(X_i) = 3*0.07 +4*0.4 +5*0.25 +6*0.28= 4.74$

In order to find the variance we need to calculate first the second moment given by:

$E(X^2) = \sum_{i=1}^n X^2_i P(X_i) = 3^2*0.07 +4^2*0.4 +5^2*0.25 +6^2*0.28= 23.36$

And the variance is given by:

$Var(X) = E(X^2) +[E(X)]^2 = 23.36 -[4.74]^2 = 0.8924$

And the deviation would be:

$Sd(X) =\sqrt{0.8924} =0.9447$

3 0

3 years ago

\ if twice a number added to 3 is divided by the number plus 7 ​, the result is five thirds. find the number.

\ if twice a number added to 3 is divided by the number plus 7 , the result is five thirds. find the number.