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2 years ago

Solve the system of equations by the addition method.

Mathematics

2 answers:

Eva8 [605]2 years ago

8 0

$\left \{ {{\frac{x}{2}-y=7 } \atop {-\frac{x}{7}+\frac{2y}{7}= -2 }} \right. \left \{ {{\frac{x}{2}.2-2y=2.7} \atop {-\frac{x}{7}.7+\frac{2y}{7}.7= -2.7}} \right. \left \{ {{x-2y=14} \atop {-x+2y=-14}} \right. \left \{ {{0x=0} \atop {y={\frac{x}{2}-7}} \right.$

ANSWER: B

ok done. Thank to me :>

larisa [96]2 years ago

7 0

Integer solution

x= 2n, y=n-7, nEZ

real solution or you can use inverse operation to have addition

y= x/2-7 y=x[multiplied by] 2+7

oh and for the first one the choice is A the second one im sorry im not sure

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The corner store is open 18 hours a day for 365 days a year. how many hours is the store open in a year?

Svetach [21]

Answer:

6570

Step-by-step explanation:

18x365=^

6 0

2 years ago

Cable Strength: A group of engineers developed a new design for a steel cable. They need to estimate the amount of weight the ca

KatRina [158]

Answer:

95% confidence interval for the mean breaking strength of the new steel cable is [763.65 lb , 772.75 lb].

Step-by-step explanation:

We are given that the engineers take a random sample of 45 cables and apply weights to each of them until they break. The mean breaking weight for the 45 cables is 768.2 lb. The standard deviation of the breaking weight for the sample is 15.1 lb.

Since, in the question it is not specified that how much confidence interval has be constructed; so we assume to be constructing of 95% confidence interval.

Firstly, the Pivotal quantity for 95% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean breaking weight = 768.2 lb

s = sample standard deviation = 15.1 lb

n = sample of cables = 45

$\mu$ = population mean breaking strength

Here for constructing 95% confidence interval we have used One-sample t test statistics as we don't know about population standard deviation.

So, 95% confidence interval for the population mean, $\mu$ is ;

P(-2.02 < $t_4_4$ < 2.02) = 0.95 {As the critical value of t at 44 degree

of freedom are -2.02 & 2.02 with P = 2.5%}

P(-2.02 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 2.02) = 0.95

P( $-2.02 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $2.02 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-2.02 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+2.02 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-2.02 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+2.02 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $768.2-2.02 \times {\frac{15.1}{\sqrt{45} } }$ , $768.2+2.02 \times {\frac{15.1}{\sqrt{45} } }$ ]

= [763.65 lb , 772.75 lb]

Therefore, 95% confidence interval for the mean breaking strength of the new steel cable is [763.65 lb , 772.75 lb].

3 0

3 years ago

The graph of the function f(x) is shown.

Elza [17]

Answer:

x = 2

x = -1.5

Step-by-step explanation:

The graph is of function f(x) = x²

Therefore, to find where the function intersects with y = 0.5x + 3,

equal the functions and solve for x:

⇒ x² = 0.5x + 3

⇒ x² - 0.5x - 3 = 0

Multiply both sides by 2:

⇒ 2x² - x - 6 = 0

Factor:

⇒ 2x² - 4x + 3x - 6 = 0

⇒ 2x(x - 2) + 3(x - 2) = 0

⇒ (x - 2)(2x + 3) = 0

Therefore:

(x - 2) = 0 ⇒ x = 2

(2x + 3) = 0 ⇒ x = -1.5

8 0

1 year ago

Please Help ASAP Combinations :(

shtirl [24]

Answer:

i) 35C17

ii)31116960

Step-by-step explanation:

i)total number of eligible are 35

now ways of chosing 17 from 35 is 35C17,

ii)Total ways of selecting 2 seniors from 7 is 7C2

and Total ways of selecting 6 juniors from 8 is 8C6

ways of selecting 4 sopho from 10 is 10C4

ways of selecting 5 freshman from 10 is 10C5

now, total way of selection come to be

10C5×10C4×8C6×7C2

i.e,252×210×28×21

i.e, 31116960

✌️:)

8 0

3 years ago

Read 2 more answers

Lyndsey ordered her school supplies online. They were delivered to her house in the box shown below.

Crank

Answer:

1350 cubic inches

Step-by-step explanation:

9*10*15

8 0

3 years ago