How do you solve x-y=1 ; x+y=3. Please Explain

2 answers:

8 0

You isolate one variable. Let's say that x will be that variable in the first equation:
x-y=1
+y +y
x=y+1
So now you have the equation for x. All you have to do is substitute it into the other:
x=y+1
(y+1)+y=3
Combine like terms and solve:
2y+1=3
-1 -1
2y=2
2y/2=2/2
y=1
Now that you have the value of one, substitute it into either of the equations to find x.
If you put it in the first:
x-1=1
+1 +1
x=2
If you put it into the other, you would get the same answer.
Therefore, y=1 and x=2

zepelin [54]3 years ago

4 0

X - y = 1
x + y = 3
________
2x = 4
__ _
2 2
x = 2
x + y = 3
2 + y = 3
-2 -2
________
y = 1
(x, y) = (2, 1)

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|x+18|=1

zepelin [54]

The absolute value, or modulus, of a number is its distance from zero, or essentially its magnitude.

The absolute value produces a positive answer.

We have this definition for the absolute value, taking into account its different values for different signs:

$|x|= \left \{ {{x, \ \ \ x \ \geq \ 0} \atop {-x, \ \ \ x \ \ \textless \ \ 0}} \right.$

Thus, for $|x+18|=1$ , we split the absolute value as such:

$x+18=1$ and $x+18=-1$

We solve each case.

$x=-17$ and $x=-19$

We check these solutions.

$|-17+18|=1\\|1|=1\\1=1$
and
$|-19+18|=1\\|-1|=1\\1=1$

5 0

3 years ago

Read 2 more answers

Anyone? please help asap i really want to finish this

yan [13]

Q. 3

$b \geqslant 2 \\$