All categories

3 years ago

How to solve 2x+y=2 and x+y=-1

1 answer:

3 0

So
2x+y=2
x+y=-1

multiply secion equation by -1
-x-y=1

add to first equation

2x-x+y-y=2+1
x=3
subsitute
3+y=-1
subtract 3
y=-4

x=3
y=-4

You might be interested in

Explain how you could use either of two operation to solve exercise 10.

wel

You want to know the factor by which 3 2/3 is multiplied to get 7 1/3.

1. You can estimate that it is 2 from 7/3 ≈ 2, then check by multiplication to see if that is right.
.. 2*(3 2/3) = 6 4/3 = 7 1/3 . . . . 2 is the correct factor.

2. You can divide 7 1/3 by 3 2/3 to see what the factor is.
.. (7 1/3)/(3 2/3) = (22/3)/(11/3) = 22/11 = 2 . . . . 2 is the factor Earl used.

3. You could see how many times you can subtract 3 2/3 from 7 1/3.
.. 7 1/3 -3 2/3 = (7 -3) +(1/3 -2/3) = 4 -1/3 = 3 2/3 . . . . . subtracting once gives 3 2/3
.. 3 2/3 -3 2/3 = 0 . . . . . . subtracting twice gives 0, so the factor is 2.

4. You could add 3 2/3 to see how many times it takes to get 7 1/3.
.. 3 2/3 +3 2/3 = (3 +3) +(2/3 +2/3) = 6 +4/3 = 7 1/3
We only need to add two values of 3 2/3 to get 7 1/3, so the factor is 2.

___
We have shown methods using multiplication, division, subtraction, addition. Take your pick.

6 0

4 years ago

A toy manufacturer wants to know how many new toys children buy each year. A sample of 1492 children was taken to study their pu

julia-pushkina [17]

By assuming the standard deviation of population 2.2 the confidence interval is 8.67 toys,8.94 toys.

Given sample size of 1492 children,99% confidence interval , sample mean of 8.8, population standard deviation=2.2.

This type of problems can be solved through z test and in z test we have to first find the z score and then p value from normal distribution table.

First we have to find the value of α which can be calculated as under:

α=(1-0.99)/2=0.005

p=1-0.005=0.995

corresponding z value will be 2.575 for p=0.995 .

Margin of error=z*x/d

where x is mean and d is standard deviation.

M=2.575*2.2/ $\sqrt{1492}$

=0.14

So the lower value will be x-M

=8.8-0.14

=8.66

=8.67 ( after rounding)

The upper value will be x+M

=8.8+0.14

=8.94

Hence the confidence interval will be 8.67 toys and 8.94 toys.

Learn more about z test at brainly.com/question/14453510

#SPJ4

8 0

2 years ago

Answer?????????????????

ANTONII [103]

So the angle A on the first diamond corresponds with angle Q, angle B with angle S, angle C with angle R, and angle D with angle P. So if angle D correspond (equals) angle P then x+34=97 and if angle R corresponds with C then 3y-13=83. From there just do some basic algebra to find the x and y values.

5 0

4 years ago

When six is subtracted from five times a number, the result is 9

Andreas93 [3]

Answer: Think it is -3/5

Step-by-step explanation:

6-5(x)=9

6-5(-3/5)=9

6+3=9

9=9

4 0

4 years ago

Read 2 more answers

e) Given the following: Let X = {1, 2, 3, 4) and a relation R on X as R= {(1,2), (2,3), (3,4)}. Find the reflexive and transitiv

Naddika [18.5K]

Answer:

The answer is $\{(1,1),(2,2),(3,3),(4,4),(1,2)(2,3)(3,4),(1,3),(1,4)\}$

Step-by-step explanation:

Remember that a reflexive relation $R\subset \mathcal{P}(X)$ , where $\mathcal{P}(X)$ is the power set of $X$ , is one which conteins the ordered pairs of the form $(a,a)$ , for $a\in X$ .

So, As the reflexive and transitive closure of $R$ (that we will denote by $\overline{R}$ ) is in particular reflexive, we must add to $R$ the elements $\{(1,1) , (2,2),(3,3),(4,4) \}$

A transitive relation $R$ is one in which if the pair $(a,b)$ and the pair $(b,c)$ are in there, then the pair $(a,c)$ must be there too.

So, to complete the relation $R$ to be reflexive and transitive we must add the pair $(1,3)$ (because $(1,2),(2,3)$ are in $R$ ), the pair $(2,4)$ , and the pair $(1,4)$ because we added the pair $(2,4)$ .

Therfore we have that $\overline{R}=\{(1,1),(2,2),(3,3),(4,4),(1,2)(2,3)(3,4),(1,3),(1,4)\}$ .

6 0

3 years ago