PLEASE HELP ME!!!!!!!!!!!!!!!!!!!

Three students used factoring to solve a quadratic equation.

DedPeter [7]

Answer:

The solution was solved correctly by Keith

The solutions of the equation are x=-5,x=-12

Step-by-step explanation:

we have

$x^{2}+17x+72=12$

Group terms that contain the same variable, and move the constant to the opposite side of the equation

$x^{2}+17x=12-72$

$x^{2}+17x=-60$

Complete the square. Remember to balance the equation by adding the same constants to each side.

$x^{2}+17x+8.5^{2} =-60+8.5^{2}$

$x^{2}+17x+72.25 =12.25$

Rewrite as perfect squares

$(x+8.5)^{2}=12.25$

square root both sides

$(x+8.5)=(+/-)3.5$

$x=-8.5(+/-)3.5$

$x=-8.5(+)3.5=-5$

$x=-8.5(-)3.5=-12$

The solution was solved correctly by Keith

The solutions of the equation are x=-5,x=-12

3 0

4 years ago

Given x(y + 2) = 3x + y, express y in terms of x.

vodka [1.7K]

Answer:

y = $\frac{x}{x-1}$

Step-by-step explanation:

Given

x(y + 2) = 3x + y ← distribute parenthesis on left side

xy + 2x = 3x + y ( subtract 2x from both sides )

xy = x + y ( subtract y from both sides )

xy - y = x ← factor out y from each term on the left side )

y(x - 1) = x ← divide both sides by (x - 1)

y = $\frac{x}{x-1}$

6 0

3 years ago

Evaluate each expression 3d-4 d=1.2

Ann [662]

Answer:

3d - 4 = -0.4

When d = 1.2

Step-by-step explanation:

Use PEMDAS to solve the equation

3(1.2) - 4

= 3.6 - 4

= -0.4

3 0

3 years ago

What is thirty more than x Algebraic expression

Bas_tet [7]

Thirty more than x = 30 + x

5 0

3 years ago

Assume that 12 people, including the husband and wife pair, apply for 4 sales positions. People are hired at random.

Iteru [2.4K]

brainly.com/question/5218999

The formula $C(n, r)= \frac{n!}{r!(n-r)!}$ , where r! is 1*2*3*...r

is the formula which gives us the total number of ways of forming groups of r objects, out of n objects.

for example, given 10 objects, there are C(10,6) ways of forming groups of 6, out of the 10 objects.

-----------------------------------------------------------------------------------------------

Selecting 4 people out of 12 can be done in :

$\displaystyle{C(12, 4)= \frac{12!}{4!8!}= \frac{12\cdot11\cdot10\cdot9\cdot8!}{4!8!}= \frac{12\cdot11\cdot10\cdot9}{4!}=11\cdot5\cdot9= 495$ many ways.

All the possible groups of 4 people, where the husband and wife are included, can be done in C(10, 2) many ways, since we only calculate the possible choices of 2 out of 10 people, to complete the groups of 4.

$\displaystyle{ C(10, 2)= \frac{10!}{2!8!}= \frac{10\cdot9}{2}=45$

Thus, the

probability that both the husband and wife are hired is 45/495=0.09

Part 2)

The probability that one is hired and the other is not =

P(husband hired, wife not hired) + P(wife hired, husband not hired)

these 2 are clearly equal, so it is enough to calculate one.

Consider the case : husband hired, wife not hired.

assuming the husband is hired, we have to calculate the possible groups of 3 that can be formed from 11-1 (the wife)=10 people.

this is

$\displaystyle{ C(10, 3)= \frac{10!}{3!7!}= \frac{10 \cdot9 \cdot8}{3\cdot2}=10\cdot3\cdot4=120$

thus,

P(husband hired, wife not hired)=120/495=0.24

thus,

The probability that one is hired and the other is not =

P(husband hired, wife not hired) + P(wife hired, husband not hired) =

0.24+0.24=0.48

Answer:

A) 0.09

B) 0.48

4 0

3 years ago