how do i slove this math equation?

Question

x-y=7
2x+y=2

please help and show steps thankyou

Answer 1

Ok I assume you want to find both x and y.

If 2x + y = 2, then if you know what x equals, you can submit that into where x is in the above equation.

Therefore rearrange x-y = 7 to make x = y + 7
So every time you see x, instead write (y+7)

So, 2(y+7) + y = 2 submit x into equation
2y + 14 +y = 2 expand brackets
3y = 2-14 combine like terms and - 14 from both sides
y = -12/3 divide both sides by 3
y = - 4


Ok so now we know what y is.

Now submit that value of y into the equation x-y = 7
x - -4 = 7
x + 4 = 7
x therefore equals 3

so x = 3 and y = -4

These are simultaneous equations. Rearrange to make x the subject of one and then submit that value into the other one, so you are left with just one variable.

There are other ways, but this example is fairly simple.

Answer 2

Ok this, is simple.
First, make the first equation into x = ...
x-y = 7
add y to both sides
x = 7+y

Now, substitute the x in the next equation with 7+y
2x + y = 2
2(7+y) + y = 2
Now distribute the 2
14 + 2y + y =2
14 + 3y = 2
Subtract 14 from both sides
3y = -12
y = -4

Now that you know y = -4, plug it back into the first equation
x-y = 7
x - (-4) = 7
x+4 = 7
subtract 4 from both sides

x = 3
y=-4

Answer 3

You have to get x by it's self by adding "y" to both sides of the equation. In the first equation this leaves you with "x = y + 7". Since you now have a value for "x", you can plug it into the second equation so that it reads like this "2(y + 7) + y = 2". Next you have to distribute (multiply) the first 2 into the parenthesis which now becomes "2y + 14 + y = 2". Add like terms (y's) next so you get "3y + 14 = 2". Next you need to get "y" alone by subtracting 14 from each side. "3y = -12". To get rid of the 3 in front of the "y" you have to multiply each side by the recipricol (opposite). The recipricol of 3 is 1/3, which leaves you with "y = -4"

Answer 4

You need to eliminate one of the variables first
Multiply the top equation by 2 so it looks like this
2x-2y=14
then you subtract the next equation from that so you have:
2x-2y=14
2x+2y=2
And your answer is -4y=12
Divide both sides by -4 and you get y=-3
Go back to the original equations and input -3 for y.
x-(-3)=7
2x+(-3)=2
For the first equation, you add -3 to 7, ending up with 4. So x=4
You will find that it's the same with equation #2
Your solution: (4,-3) or x=4 and y=-3

Answer 5

x-y = 7. First I'm gonna get Y on a side by itself. Why? because in the second equation y has no coefficient, so I can just plug that into the second equation.

-y = 7-x. multiply both sides by -1
y = x-7

Now plug this into the second equation

2x + (x-7) = 2

this gives 3x -7 = 2
now add 7 to both sides
3x = 9
x = 3

now plug the x value into the first equation

3 - y = 7

subtract 3 from both sides

-y = 4

y = -4

and you can check to see if those are right

x-y = 7

(3) - (-4) = 7 . checks out

Answer 6

First you solve either equation for a variable. For this one I would solve the first equation (x – y = 7) for x. (it doesn’t matter which variable you choose)

x – y = 7
x = 7 + y

then, you replace the answer for x in the 2nd equation.
So it becomes,

2(7 + y) + y = 2

Then you solve for y

2(7 + y) + y = 2
14 + 2y + y = 2
3y = -12
y = -4

now that you know y, replace the y in the first equation.
So it becomes,

x – (-4) = 7

then solve for x

x – (-4) = 7
x + 4 = 7
x = 3




Hope I helped!

Answer 7

What are you sloving for?

x or y?

If its x then...

2x+y=7
-y = -y

2x=7-y

2x/2 = 7-9/2

The 2's cancel out..

x= 7-9
----- <--- thats a fraction
2

I'm sorry if this is wrong, Im just trying to help..if you are solving for y then do the opposite subtract 2x from both sides..

I dont know how to solve x-y=7

Answer 8

think of of those forms of math question in diverse words. case in point interior the 1st question... 5h+2-h=22 the 1st ingredient yo pick to do is integrate tems that are alike. so we could merely rearrange what you have already got. 5h-h+2=22 next in case you pick to circulate an merchandise on the different fringe of the = sign the object ameliorations signs and warning signs. So if the object have been -3 that is going to become +3 on the different area and no rely if that's +3 then that is going to become -3. So.... 5h-h=22-2 next we would pick to integrate some greater.... while coping with factors like 5x, 5xy, 5anything, merely say to your self... I unquestionably have 5 h's minus a million h So... 4h=20 the terrific step in this technique, is looking your self the question, "4 bigger by ability of what selection equals 20???" If the question is harder like 32h=224, then we are able to apply the long hand technique. What you do in eiher case is the comparable, yet one in all them we are in a position to do in our head. to confirm what h is we attempt to get h all by ability of itself on one fringe of the = sign. we try this by ability of deviding the two factors of the equation by ability of the comparable selection. we would pick to confirm on a selection which will make the 4 circulate away. once you devide any selection by ability of itself the respond is often a million. So...... 4h/4 = 20/4 SO..... h=5

Answer 9

First, x-y=7
then that means x=7+y

now 2x + y = 2
so then 2x = 2 - y
and then x = 1 + -0.5 y

from that we have 7 + y = 1 + -0.5y

Add '-1y' to each side of the equation.
1 + -0.5y + -1y = 7 + y + -1y

Combine like terms: -0.5y + -1y = -1.5y
1 + -1.5y = 7 + y + -1y

Combine like terms: y + -1y = 0
1 + -1.5y = 7 + 0
1 + -1.5y = 7

Add '-1' to each side of the equation.
1 + -1 + -1.5y = 7 + -1

Combine like terms: 1 + -1 = 0
0 + -1.5y = 7 + -1
-1.5y = 7 + -1

Combine like terms: 7 + -1 = 6
-1.5y = 6

Divide each side by '-1.5'.
y = -4

Simplifying
y = -4

Answer 10

What you're going to do is called substitution.

First, we find out how much y is worth by isolating it

-y=(-x)+7
y=x-7

Then we substitute this y value into the second equation:

2x+(x-7)=2

Then we solve for x

2x+x-7=2
3X=2+7
3x=9
x=3

Now we substitute the x into what we decided y equaled:

y=x-7
y=(3)-7
y=(-4)

So we have decided that

x=3
y= -4

Now we check our answers by substituting them into the original equation.

3-(-4)=7 <--That's right
2(3)+(-4)=2 <--That's also right!

So, our answers are correct.