Answer:
The ordered pair is a solution to the equation
Step-by-step explanation:
Plug the ordered pair into the equation as (x,y):
y = -x + 8
4 = -4 + 8
4 = 4
Since both sides are equal to each other, then the ordered pair is a solution to the equation.
Answer:

Step-by-step explanation:
The given expression is

We need to find the simplified form of the given expression.
It can be rewritten as

Combine integers and fractions separately.

Taking LCM we get


In can be written as




Therefore, the expression
is equivalent to the given expression.
Answer:

Step-by-step explanation:
Use the Pythagorean theorem. 
a and b are the two side lengths
c is the hypotenuse (value across from the right angle)
Plug in the values that you are given.

Solve for x


x=

It would be 5sqrt2
a^2 + b^2 = c^2
5^2 + 5^2 = c^2
25 + 25 = c^2
50 = c^2
c = sqrt 50
c = 5sqrt2
Here is one way to solve for x.
Step 1) 2x^2-7=9
Step 2) 2x^2-7+7=9+7
Step 3) 2x^2=16
Step 4) (2x^2)/2=16/2
Step 5) x^2=8
Step 6) sqrt(x^2)=sqrt(8)
Step 7) |x|=sqrt(8)
Step 8) x=sqrt(8) or x=-sqrt(8)
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Below are explanations/reasons to each of the steps above.
Step 1) Original equation
Step 2) Add 7 to both sides
Step 3) Combine like terms
Step 4) Divide both sides by 2
Step 5) Simplify
Step 6) Apply the square root to both sides. The notation "sqrt" is shorthand for "square root"
Step 7) Use the rule that sqrt(x^2) = |x| for all real numbers x
Step 8) Use the rule that if |x| = k then x = k or x = -k for some fixed number k.
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The two solutions are
x = sqrt(8) or x = -sqrt(8)