Here is a riddle: “I am thinking of two numbers that add up to 5.678. The difference between them is 9.876. What are the two numbers?” The riddle can be represented with two equations. Write the equations

The two numbers is X = 7.777 and Y = -2.099.

And, the two equation is X + Y = 5.678  and X - Y = 9.876.

Given that,

Based on the above information, the calculation is as follows:

X + Y = 5.678

X - Y = 9.876

2x = 15.554  

X = 7.777    

Now  

7.777 + Y = 5.678  

Y = - 2.099

Therefore, the above should be the answers.

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X + Y = 5.678

X - Y = 9.876

The two numbers: X = 7.777   Y = -2.099

Step-by-step explanation: solve by elimination

X + Y = 5.678

X - Y = 9.876 . Add the two equations so the y cancels. Solve for x

2x = 15.554 .  Divide both sides by 2

X = 7.777    Substitute in the original equations to find Y

7.777 + y = 5.678 . Subtract 7.777 from both sides

Y = - 2.099

check in the second equation:

7.777 -(-2.099) = 9.876

7.777 + 2.099 = 9.876 True

to plot points   for x just start at the origin (middle) and go to the left however many times it say(if the number is a positive) if the number is a negative then go right however many times it says if it is 0 go nowhere

now keep you pencil there and go up however many times it says on y(if it is positive) if it is negative then go down however many times it says. if it says 0 go nowhere.

you have just plotted a point! now when you finish plotting all of them connect them with a ruler

plot each point as (-3, 7), (0,4), (3,1), (8,-4)   in the parenthesis on the left of the comma is x and the right is y.

step-by-step explanation:

to find if any function is an inverse of the other, put the first equation in as x in the next one. then simplify and solve. if at the end you get the statement y = x, then it is an inverse. if you get anything else, it is not.